Review On Atoms And Molecules

Review on Atoms and Molecules

Atoms • Miniscule! • Composed of o Protons (located in the nucleus) o Neutrons (located in the nucleus) o Electrons (located in orbitals around the nucleus) • 1st shell: max 2 electrons • 2nd shell: max 8 electrons

Molecule • Group of atoms chemically bounded to each other o Can be atoms bound to themselves • O2, H2 o Can be different atoms bounded together • H2O, NH3

Chemical Formulas • How we represent molecules • Tells us the o Type of elements in the molecule o How many of those elements in the molecule

LET’S PRACTICE! MgCl2

(Magnesium chloride)

Atoms of Magnesium: 1 Atoms of Chlorine: 2

Al2S3

(Aluminum sulfide)

Atoms of Aluminum: 2 Atoms of Sulfur: 3

PRACTICE H2SO4

(Sulfuric acid)

Atoms of Hydrogen: 2 Atoms of Sulfur: 1 Atoms of Oxygen: 4

2CH3OH

(Methanol)

2 (2 x 1) Atoms of Carbon: Atoms of Hydrogen: 8 (2 x 1) + (2 x 3) Atoms of Oxygen: 2 (2 x 1)

THIS COULD BE A LITTLE TRICKY… Al2(CO3)3

(Aluminum carbonate)

Atoms of Aluminum: Atoms of Carbon:

2 3 (1 x 3)

Atoms of Oxygen:

9 (3 x 3)

How about this one?!?! 2B2(SO4)3

(Boron Sulfate)

Atoms of Boron: Atoms of Sulfur/Sulphur:

4 (2 x 2) 6 (1 x 3 x 2)

Atoms of Oxygen:

24 (4 x 3 x 2)

Chemical Formulas • Subscript: to the bottom right of the element o Tells us how many of that element we have o If there is no subscript, it is a 1

• Coefficient: big number in front of molecule o Tells us how many molecules we have

• Brackets (parenthesis) with a subscript outside it o Tells us that each number of elements inside the bracket is multiplied by the subscript