I dii ok not under stand this please help me!

For 1: The correct answer is Model 1, 2, and 4.

For 2: The correct answer is Option 1.

Explanation:

For 1:

An element has 3 subatomic particles: electrons (E), neutrons (N) and protons (P).

Atomic number is defined as the number of protons or number of electrons.

Atoms having same number of protons are same. From the given models, Model 1, 2 and 4 have 2 protons with different neutrons. Hence, these models belong to same element.

For 2:

A compound is defined as a substance in which two or more types of elements combine in a fixed ratio. For Example:  is a compound made out of atoms of carbon and oxygen.

Hence, the correct answer is Option 2.