Explanation:

Nitrogen-14 is actually an isotope of nitrogen, so right from the start, you can SAY that it is a neutral atom.

Isotopes are atoms that have the same number of PROTONS but different numbers of neutrons in the nucleus. You know that nitrogen-14 has

7

protons in the nucleus because it is an isotope of nitrogen, which has an ATOMIC number equal to

7

.

Because nitrogen-14 is a neutral atom, the number of protons it has in its nucleus must be equal to the number of electrons that surround its nucleus.

neutral atom

⇒

no. of protons = no. of electrons

Now, in order to find the number of neutrons present in the nucleus of a nitrogen-14 atom, you must use its mass number. The mass number of an isotope is ADDED to the name of the isotope.

In this case, you have

nitrogen-

14

⇒

mass number

=

14

The mass number of an atom tells you the number of protons and neutrons LOCATED in the nucleus.

So you can say that

no. of protons + no. of neutrons

=

14

This implies that a nitrogen-14 atom contains

(

14

.

protons + neutrons

)

−

7 protons

=

7 neutrons

Now, a nitrogen atom, regardless of its mass number, will always form

3

−

anions,

N

3

−

. In other words, any nitrogen atom will take in

3

electrons to complete its octet--this happens because nitrogen is located in group

15

of the Periodic Table.