HW 4: Chemical Bonds

Which of the following are isoelectronic? (a) S2- and Ar (b) Al 3+ and Ar (c) Kr and Cl- (d) Ne and Ar

(a) S 2- and Ar

How many dots surround B in the Lewis dot symbol for Boron? (a) 2 (b) 3 (c) 5 (d) 9

(b) 3

How many dots surround Br in the Lewis dot symbol for Br - (a) 1 (b) 8 (c) 7 (d) 9

(b) 8

The structural difference between a sodium atom and a sodium ion is that the sodium ion has one (a) less proton than the sodium atom (b) less electron than the sodium atom (c) more proton and one less electron than the sodium atom (d) more proton than the sodium atom

(b) less electron than the sodium atom

Which group of elements in the periodic table is characterized by an especially stable electron arrangement? (a) 2A (b) 2B (c) 8A (d) 8B

(c) 8A

Which of the following cations is isoelectronic with S 2-? (a) Na + (b) Rb + (c) Mg 2+ (d) Ca 2+

(d) Ca 2+

Metals and nonmetals can react with each other to form ions. Complete each statement.

A potassium atom loses one electron to form a +1 ion. A sulfur atom gains two electrons to form a -2 ion.

Determine the number of electrons lost or gained when each atom forms an ion:

Be: Loses 2 electrons. Se: Gains 2 electrons. I: Gains 1 electron. As: Gains 3 electrons

Identify the number of core and valence electrons for each atom:

Core: Ar- 10 Be- 2 Br- 28. Valence: Ar- 8 Be- 2 Br- 7

For each element, identify the charge of its most common ion:

F: -1 Se: -2 K: +1 Al: +3