What is true about the element calcium(ca, atomic number 20)? choose all that apply. it has 2 valence electrons it has 4 valence electrons it is a nonmetal it is a metal

It has 2 valence electrons

It is a metal.

Explanation:

Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal.

In chemistry, a metal is an element that readily forms positive ions (cations) by losing electrons.

Calcium belongs to group 2 and would give up it's two valence electrons in reactions.

The electronic configuration is given as;

Ca : 1s2 2s2 2p6 3s2 3p6 4s2 or [Ar] 4s²

Valence electron represents the outermost electrons.

The correct options are;

It has 2 valence electrons

It is a metal.

every chemical equation adheres to the law of conservation of mass, which states that matter cannot be created or destroyed. therefore, there must be the same number of atoms of each element on each side of a chemical equation.