# Question a2918

Sep 15, 2017

Protons determine the identify of an element because the number of protons does not change during chemical reactions.

#### Explanation:

The number of protons in the atomic nuclei of an element is called the atomic number. The elements are arranged in order of increasing atomic number on the periodic table.

Protons do not determine chemical properties. Valence electrons determine the chemical properties of an element. Chemical properties are characteristics of a material that can only be observed when the material undergoes a chemical reaction, which results in a chemical change. During chemical reactions, atoms share or transfer electrons to get 8 valence electrons, which makes them stable, except for hydrogen, lithium, and beryllium, which react to get 2 valence electrons, which makes them stable.

Sep 15, 2017

Both are great answers, I would just add a statement of 'The Periodic Law' to further support what's been said ...

#### Explanation:

That is, the chemical and physical properties of the elements are a periodic function of their 'atomic number' (= protons).