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- (b) How many electrons must a sulfur atom gain to achieve an octet in its valence shell? (c) If an atom has the electron configuration 1s2 2s2 2p3, how many electrons must it gain to achieve an octet?
Problem 1
Problem 1a
For each of these Lewis symbols, indicate the group in the periodic table in which the element X belongs: (a)
Problem 2b
Illustrated are four ions — A, B, X, and Y— showing their relative ionic radii. The ions shown in red carry positive charges: a 2+ charge for A and a 1+ charge for B. Ions shown in blue carry negative charges: a 1- charge for X and a 2- charge for Y. (b) Among the combinations in part (a), which leads to the ionic compound having the largest lattice energy?
Problem 3a
A portion of a two-dimensional 'slab' of NaCl(s) is shown here (see Figure 8.2) in which the ions are numbered. (a) Which colored balls must represent sodium ions?
Problem 3d
A portion of a two-dimensional 'slab' of NaCl(s) is shown here (see Figure 8.2) in which the ions are numbered. (d) Consider ion 5. How many repulsive interactions are shown for it?
Problem 4a
The orbital diagram that follows shows the valence electrons for a 2+ ion of an element. (a) What is the element?
Problem 5
In the Lewis structure shown here, A, D, E, Q, X, and Z represent elements in the first two rows of the periodic table. Identify all six elements so that the formal charges of all atoms are zero.
- Fill in the blank with the appropriate numbers for both electrons and bonds (considering that single bonds are counted as one, double bonds as two, and triple bonds as three). (a) Fluorine has _ valence electrons and makes _ bond(s) in compounds. (b) Oxygen has _ valence electrons and makes _ bond(s) in compounds. (c) Nitrogen has _ valence electrons and makes _ bond(s) in compounds. (d) Carbon has _ valence electrons and makes _ bond(s) in compounds.
Problem 6
Problem 7a
The partial Lewis structure that follows is for a hydrocarbon molecule. In the full Lewis structure, each carbon atom satisfies the octet rule, and there are no unshared electron pairs in the molecule. The carbon—carbon bonds are labeled 1, 2, and 3. (a) How many hydrogen atoms are in the molecule?
Problem 7c
The partial Lewis structure that follows is for a hydrocarbon molecule. In the full Lewis structure, each carbon atom satisfies the octet rule, and there are no unshared electron pairs in the molecule. The carbon—carbon bonds are labeled 1, 2, and 3. (c) Which carbon—carbon bond is the strongest one?
Problem 8b
Consider the Lewis structure for the polyatomic oxyanion shown here, where X is an element from the third period (Na - Ar). By changing the overall charge, n, from 1- to 2- to 3- we get three different polyatomic ions. For each of these ions (b) determine the formal charge of the central atom, X;
Problem 9a
(a) True or false: An element's number of valence electrons is the same as its atomic number.
Problem 9b
(b) How many valence electrons does a nitrogen atom possess?
Problem 9c
(c) An atom has the electron configuration 1s22s22p63s23p2. How many valence electrons does the atom have?
Problem 10a
(a) True or false: The hydrogen atom is most stable when it has a full octet of electrons.
Problem 11b
Ammonium chloride, NH4Cl, is a very soluble salt in water. (b) Is there an N—Cl bond in solid ammonium chloride?
Problem 11c
Consider the element silicon, Si. (c) Which subshells hold the valence electrons?
Problem 12a
(a) Write the electron configuration for the element titanium, Ti. How many valence electrons does this atom possess?
Problem 12b
(b) Hafnium, Hf, is also found in group 4. Write the electron configuration for Hf.
Problem 12c
(c) Ti and Hf behave as though they possess the same number of valence electrons. Which of the subshells in the electron configuration of Hf behave as valence orbitals? Which behave as core orbitals?
Problem 13
Write the Lewis symbol for atoms of each of the following elements: (a) Te (b) Si (c) Ar (d) P
Problem 14a,b
What is the Lewis symbol for each of the following atoms or ions? (a) Be (b) Rb
Problem 14c
What is the Lewis symbol for each of the following atoms or ions? (c) Sn2+
Problem 15a
(a) Using Lewis symbols, make a sketch of the reaction between magnesium and oxygen atoms to give the ionic substance MgO
- (a) Use Lewis symbols to represent the reaction that occurs between Li and O atoms. (b) What is the chemical formula of the most likely product? (c) How many electrons are transferred? (d) Which atom loses electrons in the reaction?
Problem 16
Problem 17a
Predict the chemical formula of the ionic compound formed between the following pairs of elements: (a) Al and Cl
Problem 17b,c
Predict the chemical formula of the ionic compound formed between the following pairs of elements: (b) Mg and O (c) Zn and Cl
Problem 17d
Predict the chemical formula of the ionic compound formed between the following pairs of elements: (d) Li and O.
Problem 18a,b,c
Which ionic compound is expected to form from combining the following pairs of elements? (a) calcium and nitrogen (b) cesium and bromine (c) strontium and sulfur
Problem 18d
Which ionic compound is expected to form from combining the following pairs of elements? (d) aluminum and selenium.