What is the number balance electrons for Group IIA elements?

Answer 1

What is the valance number electrons for Group IIA elements?

When you look at the periodic table, you see 8 major columns. This represents the s and p orbitals, which hold 2 and 6 electrons respectively. The elements are placed in a column, based on the number of electrons in the s and p orbital of the outer shell. For example, Mg is in column 2 because it has 2 electrons in the s orbital of the 3rd shell. All elements in column 2 have 2 electrons in the s orbital of their outer shell. The valance number is the charge on an ion of an element. Elements in column 2 do not have a strong attraction for the 2 electrons in their outer shell. An element such as O in column 6 has a stronger attraction for electrons than Magnesium. When an atom of Mg is close enough to atom of O, and a little heat is supplied, the 2 electrons in the outer shell of Mg will move to the outer shell of the O atom giving the O atom 8 electrons in its outer shell, making it very stable.

After the 2 electrons in the outer shell of the Mg atom have moved to the outer shell of the O atom, the Mg ion has 2 less electrons in its shells than protons in the nucleus atom. Since protons have a +1 charge and electrons have a -1 charge, the Mg ion has a net charge of +2. The O atom now has 2 more electrons in its outer shell and has a net charge of -2. The charge is the valance number. All atoms of elements in GroupIIa have 2 electrons in the in their outer shell so their valence number is +2.

Do a google search for, "magnesium burning", and go to images, and you will see what happens. If you are in a chemistry class, ask your instructor to do this lab.

Answer 2

The answer is 2+.