Question

review questions:

1. complete the statement below with the appropriate word.

share ; lose ; gain; anion; octet ; cation (words can be used more than once)
chemical bonds are made by atoms ________, ______ or ________ electrons.
ionic bonds are made when a ________ and an ________ form a bond.
covalent molecules do not ________ or ______ electrons, instead they ________ electrons.
covalent molecules share electrons so that each atom can reach their __________.

1. which pair of elements is most likely to form a covalent bond?

a. sodium (na) and chlorine (cl)
b. magnesium (mg) and oxygen (o)
c. hydrogen (h) and oxygen (o)
d. potassium (k) and bromine (br)

1. which property is more characteristic of ionic compounds than covalent compounds?

a. low melting points
b. ability to conduct electricity when melted or dissolved
c. poor solubility in water
d. soft and flexible structure

Explanation:

1. Chemical bonds are formed when atoms lose, gain, or share electrons. Ionic bonds form between a cation (positively charged ion) and an anion (negatively charged ion). Covalent molecules share electrons instead of losing or gaining them. Atoms share electrons to achieve an octet (a full outer shell of 8 electrons).
2. Covalent bonds form between non - metals. Hydrogen (H) and Oxygen (O) are both non - metals. Sodium (Na), Magnesium (Mg), and Potassium (K) are metals. Chlorine (Cl), Oxygen (O), Bromine (Br) are non - metals. But in options A, B, and D, there is a metal involved which is more likely to form ionic bonds.
3. Ionic compounds conduct electricity when melted or dissolved because the ions are free to move. Covalent compounds (in non - polar form) do not conduct electricity easily. Ionic compounds have high melting points (due to strong ionic bonds), are often soluble in water (ionic - dipole interaction), and have rigid structures (due to the lattice structure of ions).

Answer:

1. Lose, Gain, Share; Cation, Anion; Lose, Gain, Share; Octet
2. C. Hydrogen (H) and Oxygen (O)
3. B. Ability to conduct electricity when melted or dissolved