Week 2 - Chemical Foundations Of Life Flashcards
Atomic number
Number of protons in an atoms nucleus
Mass number
Number of protons AND neutrons in the nucleus (mass number minus atomic number equals number of neutrons)
Matter
Has mass and takes up space
Element
unique matter form; cannot be broken down further by normal chem rxns
Valence she’ll
Outermost electron layer of an atom
Octet rule
Most shells want to hold eight electrons (most stable this way) - responsible for chemical bonds
Hydrogen
1 proton
1 electron
1 valence electrons
1 bond it wants to form
Carbon (C)
6 protons
6 electrons
4 valence electrons
4 bonds it wants to form
Oxygen (O)
8 protons
8 electrons (6 valence)
6 bonds it wants to form
Nitrogen (N)
7 protons
7 electrons (5 valence)
3 bonds it wants to form
Ions
Atoms that have gained or lost electrons
Cation
Positively charged atom (lost electrons)
Anion
Negatively charged atom (gained electrons)
Chemical bonds - 3 types
Covalent
Ionic
Hydrogen
Covalent bond
Atoms SHARE valence electrons
Single covalent - each atom contributes one electron
Double covalent - each atom contributes two electrons