Number of P.E.N.

The atomic number of an element is equal to its number of _____________.

• A. neutron

• B. proton and neutrons

• C. protons

• D. valence electron

The atomic number of Oxygen is 8. This means that the atom of Oxygen has _______.

• A. a total of eight neutrons and electrons

• B. A total of eight protons and neutrons

• C. eight neutrons in its nucleus

• D. eight protons in its nucleus

How many electrons are present in an atom of S?

• a. 16

• b. 24

• c. 32

• d. 48

Why is it important to know the number of subatomic particles in an atom?

• a. to determine the atom's size

• b. to predict its chemical properties

• c. to understand it's reactivity

• d. all of the above

A neutral Sodium-23 Atom has an atomic number of 11. How many protons, electrons, and neutrons does it have?

• A. p=23, e=23, n=11

• B. p=11, e=11, n=12

• C. p=12, e=11, n=23 

• D. p=23, e=11, n=11