Hafnium: atomic number atomic number 15
atomic number 45
osmium: atomic number
magnesium: atomic number

The question is incomplete. The complete question is as follows:

Use the periodic table to identify the name or atomic number for each element below. (Give the name, not the chemical symbol, for each element.)

hafnium: atomic number

atomic number 15

atomic number 45

osmium: atomic number

magnesium: atomic number

hafnium: atomic number  - 72

atomic number 15  - Phosphorus

atomic number 45  - Rhodium

osmium: atomic number  - 76

magnesium: atomic number - 12

Explanation:

A Periodic table is a tabular representation of elements or atoms arranged on the basis of their atomic number and atomic mass.

So according to the periodic table:

Hence, the correct answer is:

hafnium: atomic number  - 72

atomic number 15  - Phosphorus

atomic number 45  - Rhodium

osmium: atomic number  - 76

magnesium: atomic number - 12

c- cold periods in earth's history during which glaciers covered much of the surface.

explanation: