Lewis structure hclo3

Question: Draw the Lewis structure of HClO3 (by following the octet rule on all atoms) and then choose the appropriate pair of molecular geometries of the two central atoms. Your answer choice is independent of the orientation of your drawn structure. Tap here or pull up for additional resource

Lewis structure hclo3. Chemistry questions and answers. 3a. Draw the best Lewis structure for the HClO3 acid molecule. (Hint: the acidic H is bonded to O in an oxy-acid molecule). Evaluate each atom using formal charge to prove you have the best structure. Show your math work as well as your formal charge answers.

Jul 7, 2022 · July 7, 2022 by Aditi Roy. Hypochlorous acid (HClO) has a Lewis structure with a chlorine (Cl) atom at the center, bonded to an oxygen (O) atom and a hydrogen (H) atom. Cl has 7 valence electrons, O has 6, and H has 1, totaling 14 electrons. The structure shows a single Cl-O bond, a single O-H bond, and three lone pairs on Cl.

The Lewis structure for the N2H4 molecule is: The formal charge on this Lewis structure is zero indicating that this is the authentic structure. The molecular geometry for the N2H4 molecule is trigonal pyramidal and the electron geometry is tetrahedral. The hybridization of N2H4 is sp3. The dipole moment for the N2H4 molecule …There are two resonance structures ClO3 - (Chlorate ion). We start with a valid Lewis structure and then follow these general rules. For the ClO3 - resonanc...Step #1: Calculate the total number of valence electrons. Here, the given ion is ClO3- (chlorate ion). In order to draw the lewis structure of ClO3- ion, first of all you have to find the total number of valence electrons present in the ClO3- ion. (Valence electrons are the number of electrons present in the outermost shell of an atom).3.1: Lewis Structures. Page ID. Chemical bond refers to the forces holding atoms together to form molecules and solids. This force is of an electric nature, and the attraction …Long Lewis Ford in Hoover, Alabama is the premier destination for anyone looking to buy a car in Birmingham and its surrounding areas. In this article, we will explore why Long Lew...A. Definition and concept. The ClO3- Lewis structure refers to the diagrammatic representation of the chlorate ion’s molecular structure. It shows the arrangement of atoms, electrons, and their bonds in a simple and clear way. The Lewis structure helps to determine the ion’s polarity, shape, and reactivity.A quick explanation of the molecular geometry of HClO3 (Chloric acid) including a description of the HClO3 bond angles.Looking at the HClO3 Lewis structure w...

HClO3 has 1+7+ (3*6) = 26 valence electrons. Start by putting Cl in the center (since it's the least electronegative), then draw the three oxygen around the Cl. For one of the oxygen, add the hydrogen next to it. Connect each of them with a single bond, and then fill the rest of the lone pairs. However, if you calculate the formal charges, two ...Drawing the Lewis Structure for H 2 SO 3. In H 2 SO 3 Lewis structure Sulfur is least electron electronegative atom and goes in the center of the Lewis structure. When we have an H (or H2) in front of a polyatomic molecule (like CO 3, SO 4, NO 2, etc.) we know that it's an acid. This means that the Hydrogen atoms will be attached to the outside ... The structure of H ClO3 (chloric Acid) is shown below. H atom is attached to O atom via a sigma bond. There are two Cl = O double bonds and one Cl −O single bond. Cl atom has one lone pair and 5 bond pairs of electrons. The geometry around Cl is pyramidal. To calculate the oxidation numbers for HClO3, count the number of atoms, draw the lewis structure by adding bonds, assign electrons from each bond, and count the number of electrons assigned to each atom. Count Atoms Use the chemical formula, HClO 3, to count the number of atoms of each element.Science. Chemistry. Chemistry questions and answers. Question 1 5 pts From the Lewis structures shown below select those that represent the resonance structures of HIO, (it does not have to be the lowest energy structure). CH-1-0-0 (H-0-1-0 (iv) H-0-1=0 a) H-0-0-1 WH-0-1-0 All (1) and (iv) (iv) and (v) (li) and (ii) (1) and (II) Question 2 5 ... Lewis Structure Finder. Added Jun 9, 2014 by WebTester in Chemistry. This widget gets the Lewis structure of chemical compounds. Send feedback | Visit Wolfram|Alpha. Get the free "Lewis Structure Finder" widget for your website, blog, Wordpress, Blogger, or iGoogle. Find more Chemistry widgets in Wolfram|Alpha. The structure on the right is the Lewis electron structure, or Lewis structure, for H 2 O. With two bonding pairs and two lone pairs, the oxygen atom has now completed its octet. Moreover, by sharing a bonding pair with oxygen, each hydrogen atom now has a full valence shell of two electrons. Chemists usually indicate a bonding pair by a single ...

In this article, we will discuss about xeo2f2 lewis structure, hybridization, formal charge, and its geometry. Xenon dioxide difluoride, sometimes known as XeO 2 F 2, is an inorganic molecule with the chemical formula XeO 2 F 2.The partial hydrolysis of Xenon hexafluoride produces it, as shown in the following reaction: XeF 6 +2H 2 O —> …To calculate the oxidation numbers for HClO3, count the number of atoms, draw the lewis structure by adding bonds, assign electrons from each bond, and count the number of electrons assigned to each atom. Count Atoms Use the chemical formula, HClO 3, to count the number of atoms of each element.Chemistry questions and answers. Draw the Lewis structure for HClO_3 from the skeletal template prated below. If the valence shells are filled to the usual limit (maximum of 8), what is the sum of the absolute values of all the formal charges in the molecule? a. 0 …Question: Draw the Lewis structure of HClO3 (by following the octet rule on all atoms) and then choose the appropriate pair of molecular geometries of the two central atoms. Your answer choice is independent of the orientation of your drawn structure. There are 3 steps to solve this one.

Eliza st jude patient today.

HClO3 Lewis Structure [ENDORSED] Moderators: Chem_Mod, Chem_Admin. 5 posts • Page 1 of 1. emilyyribarren1k Posts: 56 Joined: Thu Oct 01, 2020 5:10 am Been upvoted: 1 time. HClO3 Lewis Structure. Post by emilyyribarren1k » Fri Dec 11, 2020 11:28 pm .Nov 6, 2019 · Lewis Structure HClO3. Moderators: Chem_Mod, Chem_Admin. 3 posts • Page 1 of 1. AnnikaMittelhauser4E Posts: 50 Joined: Fri Aug 30, 2019 7:18 am. Lewis Structure HClO3. That the stability of the conjugate base increases with the number of oxygens may be seen from the charge distribution diagrams and Lewis bonding models for the chlorine oxyanions shown in figure \(\PageIndex{2}\) . As the negative charge is spread over more oxygen atoms it becomes increasingly diffuse.Hence in a HCO3- ion, Valence electrons given by Hydrogen (H) atom = 1. Valence electrons given by Carbon (C) atom = 4. Valence electrons given by each Oxygen (O) atom = 6. Electron due to -1 charge, 1 more electron is added. So, total number of Valence electrons in HCO3- ion = 1 + 4 + 6 (3) + 1 = 24.HClO4 is still neutral because we can look at the formal charges in the Lewis structure to determine the charge of HClO4. The Cl atom would have three double bonds with three oxygen atoms and one single bond with OH, causing the formal charge of Cl to be 0 (7- (0+14/2)). All the oxygens will also have a formal charge of 0 because all of them ...

Step 3: Connect each atoms by putting an electron pair between them. Now in the HClO4 molecule, you have to put the electron pairs between the oxygen (O) & hydrogen (H) atom and between the oxygen (O) & chlorine (Cl) atoms. This indicates that these atoms are chemically bonded with each other in a HClO4 molecule.80. Draw the Lewis structure of HClO₃ (by following the octet rule on all atoms) and then choose the appropriate pair of molecular geometries of the two central atoms. Your answer choice is independent of the orientation of your drawn structure. Problem 70QRT: Use Lewis structures and VSEPR theory to predict the electron-region and molecular ...The Lewis dot structure has a central carbon that is bonded to 3 oxygens. Each oxygen has 3 lone pairs. The molecule is inside square brackets and has a charge of minus 2. 5. No electrons are left for the central atom. 6. At this point, the carbon atom has only 6 valence electrons, so we must take one lone pair from an oxygen and use it to … Lewis Structure Finder. Added Jun 9, 2014 by WebTester in Chemistry. This widget gets the Lewis structure of chemical compounds. Send feedback | Visit Wolfram|Alpha. Get the free "Lewis Structure Finder" widget for your website, blog, Wordpress, Blogger, or iGoogle. Find more Chemistry widgets in Wolfram|Alpha. You'll get a detailed solution from a subject matter expert that helps you learn core concepts. See Answer. Question: Draw the structure for chloric acid, HClO3. Optimize formal charges. Draw the structure for chloric acid, HClO3. Optimize formal charges. There are 2 steps to solve this one. Expert-verified. 83% (6 ratings) Postby Kian K » Wed Nov 08, 2023 9:41 pm. If the H was on the Cl it would have a negative formal charge and oxygen as well would have a negative charge, giving oxygen 2 bonds makes it neutral. Top. 3 posts • Page 1 of 1. Return to “Lewis Structures”.The information on this page is fact-checked. The Lewis structure of HClO4 contains three double bonds and two single bonds, with chlorine in the center, and hydrogen and four oxygens on either side. There are two lone pairs on each oxygen atom, and chlorine atom and hydrogen atom do not have any lone pair. CHLORIC ACID. Molecular Formula HClO. Average mass 84.459 Da. Monoisotopic mass 83.961426 Da. ChemSpider ID 18513. Exercise 10.4.1 10.4. 1. Use Lewis electron dot diagrams to illustrate the covalent bond formation in Cl 2. Answer. When working with covalent structures, it sometimes looks like you have leftover electrons. You apply the rules you learned so far, and there are still some electrons that remain unattached.One of the fundamental concepts in chemistry is the Lewis structure, which is a diagram that shows the bonding between atoms in a molecule and the lone pairs of electrons that may exist. In this article, we will discuss the Lewis structure for HClO3, a compound commonly known as chloric acid.

The Lewis structure for the N2H4 molecule is: The formal charge on this Lewis structure is zero indicating that this is the authentic structure. The molecular geometry for the N2H4 molecule is trigonal pyramidal and the electron geometry is tetrahedral. The hybridization of N2H4 is sp3. The dipole moment for the N2H4 molecule …

If you’re in the market for new curtains, there’s no better time to shop than during a John Lewis curtains sale. Known for their high-quality and stylish home decor, John Lewis off...The HClO Lewis dot structure shows that oxygen is the central atom that is forming single covalent bonds with chlorine and hydrogen H-O-Cl. The total valence electrons of HClO are 14. The formal ...Find step-by-step Chemistry solutions and your answer to the following textbook question: Draw the structure for chloric acid, $\ce{HClO3}$. Optimize formal charges.. ... Lewis structure is a diagram that shows how the valence electrons are arranged around the atoms in a given molecule. Bonding electrons are represented as a line between two ...3a.Draw the best Lewis structure for the HClO3 acid molecule. (Hint: the acidic H is bonded to O in an oxy-acid molecule).Evaluate each atom using formal charge to prove you have the best structure. Show your math work as well as your formal charge answers. 3b. Draw all the resonance structures for the ClO3– polyatomic anion.The Lewis dot structure for Cl2, the chemical formula for chlorine gas, is written with two Cl symbols, each of which is surrounded by three pairs of dots, connected by a single li...If you’re in the market for a new table lamp, John Lewis is a brand that you can trust. Known for their high-quality and stylish home furnishings, John Lewis offers a wide selectio...Sekarang mari kita lanjutkan ke langkah terakhir untuk memeriksa apakah struktur Lewis HClO3 stabil atau tidak. Langkah 6: Periksa stabilitas struktur Lewis. Sekarang Anda telah sampai pada langkah terakhir di mana Anda perlu memeriksa stabilitas struktur Lewis HClO3. Stabilitas struktur Lewis dapat diverifikasi dengan …Are you looking to add a touch of sophistication and elegance to your home? Look no further than John Lewis large table lamps. These beautifully crafted lamps not only provide func...Step #4: Complete the octet (or duplet) on outside atoms. If the valence electrons are left, then put the valence electrons pair on the central atom. Don’t worry, I’ll explain! In the Lewis structure of H2SO3, the outer atoms are hydrogen atom as well as oxygen atom. Hydrogen already has a duplet (see below image).

Perkins mud bog 2023 dates.

Harbor freight 4 july sale.

The Lewis Structure of Hydrogen Sulfide is easy to draw and understand. In this compound, both the hydrogen atoms require one electron to make the covalent bond with Sulfur. The Lewis structure of H2S is similar to H 2 S. Sulfur needs eight electrons to fulfill the requirements for Octet Rule. But Hydrogen only requires a single electron to ...Lewis structure for HOCl. The properly way to determine the Lewis structure, based on this example, is: Total valence electrons: 7 + 6 + 1 = 14 7 + 6 + 1 = 14. Total electrons needed for octets/doublets: 8 …It's always a good idea to start by drawing the Lewis structure of the molecule, this will give a good idea of what it's going on interms of molecular geometry.. Keep im mind that Lewis structures are not meant to convey geometry, the are just helpful in determining geometry!. In the case of chloric acid, #"HClO"_3#, you can draw several …Are you on the hunt for the best deals and sales at John Lewis UK? Look no further. In this shopper’s guide, we’ll explore the top ways to save money and find great bargains at thi...A step-by-step explanation of how to draw the HClO4 Lewis Structure (Perchloric Acid).When we have an H (or H2) in front of a polyatomic molecule (like CO3, ...Lewis electron dot diagrams use dots to represent valence electrons around an atomic symbol. Lewis electron dot diagrams for ions have less (for cations) or more (for anions) dots than the corresponding atom. This page titled 9.2: Lewis Electron Dot Diagrams is shared under a CC BY-NC-SA 3.0 license and was authored, remixed, …You'll get a detailed solution from a subject matter expert that helps you learn core concepts. See Answer. Question: Draw the structure for chloric acid, HClO3. Optimize formal charges. Draw the structure for chloric acid, HClO3. Optimize formal charges. There are 2 steps to solve this one. Expert-verified. 83% (6 ratings)Using the Lewis structures for HClO, HClO2, HClO3 and HClO4, explain why HClO3 and HClO4 are strong acids, but the other two are not. Here’s the best way to solve it. 100% (3 ratings) Share Share. All the above are the oxyacids of chlorine. If we observer them we canv easily make out that there is an increase …. View the full answer.With its rich history and commitment to quality, John Lewis UK has become a beloved retailer for shoppers across the country. From fashion and beauty to home decor and electronics,...This problem has been solved! You'll get a detailed solution from a subject matter expert that helps you learn core concepts. Question: Identify the correct Lewis structure for C2H2. O H-c-h-c: H-Ö=c-H H-ċ-ċ-H H-CEC-H O O H CEC: Н. There are 2 steps to solve this one. ….

Chemistry questions and answers. 2) A) Draw the Lewis structure of HCIO, where the structure obeys octet rule. (2 pts) 1 B) Draw the structure where the formal charges are minimized. Draw in the bond dipoles. C) Determine the Steric number or electron geometry around the central atom.CHLORIC ACID. Molecular Formula HClO. Average mass 84.459 Da. Monoisotopic mass 83.961426 Da. ChemSpider ID 18513.A Lewis dot structure for SeO3 is drawn with an Se in the center, with two lines connecting it to two Os and one double line connecting it to an O. The Os connected by single lines...When choosing a corporate structure, one factor is taxes: Are they levied before or after profits get distributed to owners. By clicking "TRY IT", I agree to receive newsletters an...ClO3- or chlorine trioxide or chlorate is a monovalent inorganic anion that is soluble in water. Chlorine trioxide is non-combustible in nature but when it gets …A step-by-step explanation of how to draw the IO3- Lewis Dot Structure (Iodate Ion).For the IO3- structure use the periodic table to find the total number of...3.1: Lewis Structures. Page ID. Chemical bond refers to the forces holding atoms together to form molecules and solids. This force is of an electric nature, and the attraction …The given molecular formula is HClO3. The molecular name for the given compound is chloric acid. The best and most stable lewis structure of HClO3 with minimized formal charges isThe information on this page is fact-checked. The Lewis structure of HClO3 contains two double bonds and two single bonds, with chlorine in the center, and three oxygens and hydrogen on either side. There are two lone pairs on each oxygen atom, one lone pair on the chlorine atom, and the hydrogen atom does not have any lone pair. Lewis structure hclo3, In this problem, we need to draw the Lewis structure of H C l O X 3 \ce{HClO3} HClO X 3 , and find the molecular geometry of the two central atoms. Chlorine is in the group 7 A \ce{7A} 7 A , so it has 7 7 7 valence electrons, oxygen is in the group 6 A \ce{6A} 6 A , and it has 6 6 6 valence electrons, and hydrogen has 1 1 1 valence electron., Determine the Lewis Dot Structure for chloric acid:HClO3. Skip to main content. General Chemistry Start typing, then use the up and down arrows to select an option from the list.? ... HNO3 Lewis Structure - How to …, Yakuza Structure - Yakuza clans have a single patriarch (kumicho) who rules the Yakuza clans, supported by various underbosses. Learn more about Yakuza clans. Advertisement A Yaku..., What is the term structure of interest rates? From a flat term structure to inverted yield curves, discover how interest rates influence bond values. The term structure of interest..., Define covalent bond. Illustrate covalent bond formation with Lewis electron dot diagrams. Ionic bonding typically occurs when it is easy for one atom to lose one or …, A step-by-step explanation of how to draw the ClO4- Lewis Structure (Perchlorate Ion). The ClO4-Lewis structure is a good structure to help you understand..., The Lewis structure of ClO3- helps us determine the bond angles and molecular geometry of the ion. In ClO3-, the central chlorine atom is surrounded by three oxygen atoms. The arrangement of these atoms gives rise to a trigonal pyramidal molecular geometry. The bond angles in ClO3- are approximately: O-Cl-O: 109.5°. O-Cl=O: 120°., Chris P Schaller, Ph.D., (College of Saint Benedict / Saint John's University) Andreas Hagen (via StackExchange) 3.1: Lewis Structures is shared under a not declared license and was authored, remixed, and/or curated by LibreTexts. hemical bond refers to the forces holding atoms together to form molecules and solids., HClO3 has 1+7+ (3*6) = 26 valence electrons. Start by putting Cl in the center (since it's the least electronegative), then draw the three oxygen around the Cl. For one of the oxygen, add the hydrogen next to it. Connect each of them with a single bond, and then fill the rest of the lone pairs. However, if you calculate the formal charges, two ..., A Lewis structure is a way to show how atoms share electrons when they form a molecule. Lewis structures show all of the valence electrons in an atom or molecule. The valence electrons are the electrons in the outermost shell. For representative elements, the number of valence electrons equals the group number on the periodic table., Chlorine trifluoride or ClF3 is an extremely reactive chemical compound with several varied applications and unique physical and chemical compounds. An interhalogen compound having both Cl and F, it has a density of around 3.79 g/l and a molar mass of 92.45 g/mol. ClF3 exhibits a strong suffocating pungent odor and varies from colorless …, Chloric acid is a colorless liquid. It will accelerate the burning of combustible materials and can ignite most on contact. It is corrosive to metals and tissue. It is used as a reagent in chemical analysis and to make other chemicals. Chloric acid is a chlorine oxoacid. It is a conjugate acid of a chlorate., In this problem, we need to draw the Lewis structure of H C l O X 3 \ce{HClO3} HClO X 3 , and find the molecular geometry of the two central atoms. Chlorine is in the group 7 A \ce{7A} 7 A , so it has 7 7 7 valence electrons, oxygen is in the group 6 A \ce{6A} 6 A , and it has 6 6 6 valence electrons, and hydrogen has 1 1 1 valence electron., 13 Dec 2012 ... Lewis Dot Structures for Covalent Compounds - Part 1 - This awesome video shows how to draw lewis dot structures for covalent compounds., 3. ) Lewis Structure. Lewis structure of sulfurous acid (H 2 SO 3) contains two O-H bonds,one S=O bond, two S-O bonds.. Also, there is one lone pairs on sulfur atom. Concept of number of total valence electrons of atoms are used to draw lewis structure of H 2 SO 3. Each step of drawing the lewis structure of H 2 SO 3 is explained in detail in ..., Figure 3.1.1 3.1. 1: Lewis dot structure of atoms comprising ammonia and the dot structure of the molecule. (Kathryn Haas; CC-NC-BY-SA) The drawing of Lewis electron-dot structures is guided largely by the octet rule: that atoms form bonds to achieve eight electrons in their valence shell. For many elements, a full valence shell has an electron ..., A Lewis diagram shows how the valence electrons are distributed around the atoms in a molecule. Shared pairs of electrons are drawn as lines between atoms, while lone pairs of electrons are drawn as dots next to atoms. When constructing a Lewis diagram, keep in mind the octet rule, which refers to the tendency of atoms to gain, lose, or share ... , The Lewis structure for the N2H4 molecule is: The formal charge on this Lewis structure is zero indicating that this is the authentic structure. The molecular geometry for the N2H4 molecule is trigonal pyramidal and the electron geometry is tetrahedral. The hybridization of N2H4 is sp3. The dipole moment for the N2H4 molecule …, Question: A) Draw the Lewis structure of HClO3 where the structure obeys octet rule. What is the electronic geometry?B) Draw the structure where the formal charges are minimized. Draw in the bond dipoles. What is the electronic geometry?C) Determine the Steric number and molecular geometry around the central atom in part B ..., The Lewis structure of ClO3- helps us determine the bond angles and molecular geometry of the ion. In ClO3-, the central chlorine atom is surrounded by three oxygen atoms. The arrangement of these atoms gives rise to a trigonal pyramidal molecular geometry. The bond angles in ClO3- are approximately: O-Cl-O: 109.5°. O-Cl=O: 120°., Sep 16, 2022 · Exercise 10.4.1 10.4. 1. Use Lewis electron dot diagrams to illustrate the covalent bond formation in Cl 2. Answer. When working with covalent structures, it sometimes looks like you have leftover electrons. You apply the rules you learned so far, and there are still some electrons that remain unattached. , Lewis Symbols. We use Lewis symbols to describe valence electron configurations of atoms and monatomic ions. A Lewis symbol consists of an elemental symbol surrounded by one dot for each of its valence electrons:. Figure \(\PageIndex{1}\) shows the Lewis symbols for the elements of the third period of the periodic table., This problem has been solved! You'll get a detailed solution from a subject matter expert that helps you learn core concepts. Question: Draw the lewis structure for one of the possible resonance structure for the chlorate ion (ClO3^-). Minimize the formal charge assigned to each atom. Include all nonzero formal charges., KClO 3 lewis structure angle. Lewis structure angle is measured for covalent compound between the overlapping hybrid orbitals which form bond. Let us find if we can measure this for KClO 3.. KClO 3 lewis structure angle can not be determined like covalent molecules with help of VSEPR theory.Here oppositely charged ions arranged …, The information on this page is fact-checked. The Lewis structure of HClO3 contains two double bonds and two single bonds, with chlorine in the center, and three oxygens and hydrogen on either side. There are two lone pairs on each oxygen atom, one lone pair on the chlorine atom, and the hydrogen atom does not have any lone pair., When it comes to finding the perfect recliner for your home, John Lewis is a great place to start. With a wide selection of styles and sizes, you’re sure to find something that fit..., Lewis structure of ClO3- (or Chlorate ion) contains two double bonds and one single bond between the Chlorine (Cl) atom and Oxygen (O) atom. The Chlorine atom (Cl) is at the center and it is surrounded by 3 Oxygen atoms (O). The Chlorine atom has 1 lone pair. And the single bonded oxygen atom has -1 formal charge., Jun 15, 2013 · The ClO3- Lewis structure is a good structure to help you understand w... A step-by-step explanation of how to draw the ClO3- Lewis Structure (Chlorate Ion). , The Lewis structure of C2, the chemical formula for diatomic carbon, is written with two Cs connected by two straight lines. Each C also contains one pair of dots, for a total of t..., In the Lewis structure for HClO 3 there are a total of 26 valence electrons. See the Big List of Lewis Structures Transcript: This is the HClO3 Lewis structure., In the HClO3 lewis structure, Cl is in a +5 oxidation state and it is its highest oxidation state so, it can behave oxidizing agent, can undergo reduction, and oxidized other substituents. The pka value of HClO3 is very low almost negative, so it is a strong inorganic acid. the central Cl atom is sp3 hybridized here., We drew the lewis structure for HClO3 in lecture today and I was wondering why the H needed to bond with one of the oxygen's as opposed to the Cl to complete its octet? Top. 405961647 Posts: 50 Joined: Fri Sep 29, 2023 6:30 pm. Re: HClO3. Post by 405961647 » Fri Dec 08, 2023 10:16 pm ., In the HClO3 lewis structure, only Cl and O atoms contain the lone pair only. The total lone pairs of the HClO3 lewis structure is the summation of the lone pairs of …