Ba2Si3C CHe2 mistry

Introduction

• Laws of chemistry govern the structure and function of all living things!

Atomsa. simplest part of an element that

retains all the properties of that element

b. determine the behavior of matter

c. subatomic particles protons (p+) positively charged particles

neutrons (nº) no charge

electrons (e-) negatively charged particles

make up 99% of the mass

d. Net electrical charge of an atom is zero because the number of p+ = e- e. e- located in orbitals (3-D space surrounding atom) 90% of timef. Electrons are the only particles involved in chemical reactions.

Orbital Shellsa. valence electrons e- in outermost shell

b. valence shells are complete (happy) when full

c. 1st orbital = 2 e- 2nd orbital = 8 e- 3rd orbital = 8 e- 4th orbital = 16 e-

methane CH4

C

H

H

H

H

Bohr Model

nucleus 1st shell maximum of 2 electrons

2nd shell maximum of 8 electrons

3rd shell maximum of 8 electrons

4th shell maximum of 16 electrons

Mattera. Everything in the universe is

made of matter.b. Anything that occupies space

and has mass.c. Building blocks = atomsd. Properties:

mass= quantity of matter volume= amount of space occupied density= mass/volume weight= pull of gravity

Solid

Strong bonds

Liquids

Weak bonds

Gas

No bonds

Plasma

- +

+ -Ionization

+

electron

proton

Phases of Matter

Forms of Matter

a. element = pure substance made of only one kind of atom– cannot be chemically broken down into other

substances– over 100 elements, but less than 30 support

life– Carbon Hydrogen Oxygen Nitrogen (more than 90% of the mass of living things is made of these four elements)

6C

Carbon12.0107

1H

Hydrogen1.00794

8O

Oxygen15.9994

7N

Nitrogen14.00674

b. Compound = two or more elements in a fixed ratio Examples: H O, CO , NaCl2 2

Chemical formulas

ratio of water = 2 hydrogenatoms to one oxygen atom

c. Molecule = simplest part of a substance that retains all the properties of that substance

H O – more than one type of atom2

Forms both a molecule and a compound

d. Both represent different combinations of atoms.

O - one type of atom2

Forms a molecule but not a compound.

Periodic Table of Elements

a. Atomic Number (unique for each element)= # of protons in the nucleus= # of electrons in a neutral atom

b. Atomic Mass = # of protons and neutrons in the nucleus

6C

Carbon12.0107

Atomic number

Chemical symbol

Name

Atomic Mass

Al27

13

Mass number

Atomic number 13 protons OR

13 electrons

13 protons AND14 neutrons

Ion

a. atoms that gain or lose electrons

b. have an unequal number of p+ and e-

c. have net negative or positive charge

d. very reactive atoms

SPECIAL ATOMS

Na Cl

NaNa

sodium ion Na+

sodium

Isotopes

a. atoms with the same number of protons but a different number of neutrons; different mass

b. unstable nucleus; releases radiation; can damage living tissue

c. Used in medicine and research

1. biological tracers

2. dating objects

3. treating cancer

(SPECIAL ATOMS) 6P6N

Carbon 12

6P8N

Carbon 14

Formation of Compounds by Bonding

a. compounds have 2 or more elements in a fixed ratio

b. have new properties from atomsc. covalent bonds = 2 atoms share

one or more valence electrons (forms molecules); very strong bond

d. ionic bonds = transfer of electrons; formed by electrical attraction between two oppositely charged ions; (forms crystals)