chapter 2 bio: the chemical basis of life

Atomic Number

number of protons in the nucleus

Mass Number

Number of protons + neutrons

How do you find neutrons?

Mass number - atomic number

What makes an isotope

adding/removing a neutron

What is atomic weight?

Weighted average of an element’s isotopes

How do you calculate atomic weight

isotope mass + decimal abundance

Where do electrons likely move in the atom and how many electrons can they each hold?

Electrons move in an orbital that can only hold 2 electrons per orbital.

What are valence shells and what are the electrons there called

Outermost shell in atom. The electrons found there re called valence electrons.

what’s a chemically inert element and where are they on the periodic table

Means they aren’t reactive and they are all the way to the right of the periodic table. The outermost energy level is complete

What’s a chemically reactive elements and what do they want more of

Their outermost energy shell is is incomplete and wants more electrons