Covalent and Ionic Bonds

Berea Arts and Sciences High School
Covalent and Ionic Bonds Problem Set

Notes

Ionic bond – a strong attractive force holding ions together. An ionic bond can
form between two atoms by the transfer of electrons from the valence shell of one atom to the valence shell of the other

Covalent bond – a strong attractive force that holds two atoms together by their
sharing of electrons. These bonding electrons are attracted simultaneously to both atomic nuclei, and they spend part of the time near one atom and part of the time near the other

Electronegativities – the unequal abilities of the atoms to draw bonding electrons
to themselves

Lewis electron-dot formulas – simple representations of the valence-shell
electrons of atoms in molecules and ions and are useful for describing the covalent bonding in substances

Problem Set.

1. For each of the following pairs of elements, state whether the binary compound formed is likely to be ionic or covalent. Give the formula and name of the compound.

a. Sr,O b. C,Br c. Ga, F d. N, Br

2. Give the Lewis formula for the arsenate ion, AsO3-4. Write the formula of lead(II) arsenate.

3. Iodic acid, HIO3, is a colorless, crystalline compound. What is the electron dot formula of iodic acid?

4. Write electron dot formulas for the following:

a. SeOCl2 b. CSe2 c. GaCl-4 d. C2-2

5. Why do most monoatomic cations of the main-group elements have a charge equal to the group number? Why do most monoatomic anions of these elements have a charge equal to the group number minus 8?

6. Describe the formation of a covalent bond in H2 from atoms. What does it mean to say that the bonding electrons are shared by the two atoms?