Use the following key to classify each of the elements below in its elemental form: a. Discrete atoms
b. Molecules
c. Metallic lattice
d. Covalent Network.

1. Phosporus
2. Bromine
3. Hydrogen
4. Krypton

Explanation:

Given set of elements in one column and their classification in another column.

1. Phosporus                         c.Metallic lattice

2. Bromine                           d.Covalent network.

3. Hydrogen                          b. Molecules

4. Krypton                              a. Discrete atoms

Since Krypton is an inert gas and it exists in discrete atoms.

Hydrogen exists as a diatomic gas.

Bromine exists as Br_2 liquid and is held by covalent bonds.

Phosphorus exists as P_4 molecules and it exits as a metallic lattice.

the answer is symmetrical : )