Question

3. Look at the positions of calcium, beryllium, and magnesium on the periodic table. Based on their locations, predict how many valence electrons these elements have and predict what the reactivity of these elements will generally be.

Answer 1

Ca= 2 ve
Be=2 ve
Mg=2 ve because they are in Group 2a.
 They are slightly less reactive than Group 1a, but more dense that Group 1a.

Answer 2

Explanation:

It is known that beryllium, calcium and magnesium are all group 2 elements.

Atomic number of Be is 4, magnesium has 12 and calcium has atomic number 20.

So, they contain 2 valence electrons and in order to attain stability they readily lose their valence electrons.

As a result, they tend to form an ion with +2 charge.

Since, it is easy to lose two electrons to attain stability hence, elements of group 2 are very reactive in nature.