The median Social Security benefit was $16,295 for men and $11,999 for women in 2012, AARP found. Retirement savings. Just under a third (30 percent) of retirees receive income from either a traditional pension or take withdrawals from a retirement savings account such as a 401(k) or individual retirement account.
The Sodium atom. 1  The Na atom has an equal number of electrons and protons (11 e-and 11 p+). 2  This atom too is unstable because the outer valance shell of electrons has only one electron in it. 3  To be stable the outer shell of electrons should have eight electrons.
Quick Answer. Sodium is a metallic element on the periodic table with an atomic number of 11 and an atomic mass of 22.98 amu. This atomic mass is calculated by adding together the number of protons and neutrons present in the atom's nucleus. Sodium was discovered by Sir Humphrey Davy in 1807.