Chemical equations
Substances at the start of a reaction
Reactants
Negatively charged particle
Electron
Law stating mass is conserved
Law of conservation of mass
Unstable atoms releasing energy
Radioactivity
Pure substance made of 1 type of atom
Element
Substances formed in a reaction
Products
Particle with positive charge
Proton
4.60 g + 7.09 g
11.69 grams
Time for half a sample to decay
Half-Life
Two or more elements chemically bonded
Compound
Write equations using words instead of formulas
Word equation
Mass number- atomic number
number of neutrons
434 g → 402 g
32g
Type of radiation stopped by paper
Alpha radiation
Groups of atoms bonded together
Molecule
Why equations are balanced
Law of conservation of mass
Electron arrangement 2,8,18
? + 16.0 g → 40.3 g
24.3
Why Isotopes decay
unstable nuclei
S, l, g, aq
what are states of matter
Meaning of “3” in 3H₂O
3 molecules
Same protons different neutrons, same element
Isotopes
What must stay equal in reactions
number of atoms in each element
One danger and one use
cell damage, medical use
Why green chemistry matters
reduces environmental impact and waste