In each of the blanks below, only enter a numerical value.

Question

In each of the blanks below, only enter a numerical value. 

In a tin (Sn) atom, there are _______ valence electrons and _______ core electrons. 

Answer 1

Hi Ely! The easiest way to solve this is to look at the periodic table and find tin (Sn). Valence electrons are those in the outermost shell of the atom, while core electrons are the electrons in every other shell the atom has. As you move over to the right on the periodic table, every atom gains one valence electron (Make sure to skip the D group, the metals in the middle of the table). When you look where tin is, it is in Row 5. Rubidium has 1 valence electron, Strontium has 2 valence electrons, Indium has 3 valence electrons, and Tin has 4 valence electrons.

The atomic number is the number of protons that an atom has. If it is electrically neutral (like tin in the resting state), then an atom has the same number of electrons. Subtracting 4 from 50, we get that tin has 46 core electrons.

Hope this helps!