An ion has a 3- charge and 18 electrons. what is the identity of the element?

The given element is phosphorus.

Explanation:

We are given:

Number of electron in an ion = 18 electrons

Charge on the ion = -3

Atomic number is defined as the number of protons or electrons that are present in a neutral atom.

Atomic number = number of protons = number of electrons

An ion is formed when an atom looses or gains electron.

To calculate the atomic number for the given anion, we use the equation:

Number of electrons in a neutral atom = Number of electrons in an ion + charge

Number of electrons in a neutral atom = 18 - 3 = 15

Hence, the given element is phosphorus.

1.solid

2.carbon dioxide

3.helium