Use the periodic table to identify the number of core electrons and the number of valence electrons in each case below. Magnesium (Mg): 1s22s22p63s2

Iknow the answer to 13 is b and 14 is d. i just need to know why the correct answers are correct

Which type of orbits are found in the principal energy level n = 2 a - s b - s, f c - s, d d - s, p e - s, p, d

Select all that apply. a beta particle: is electromagnetic energy is an electron has zero charge is emitted from the nucleus has a +2 charge has a -1 charge