BASIC CHEMISTRYHonors Biology

Recall: Levels of Organization

Biology Depends on Chemistry In our biosphere, everything is made of atoms

Through the interaction of chemicals we can better understand our biosphere

Give an example from what we have already done in Bio.

2 MAIN AREAS1.NUCLEUS

-center2. ENERGY LEVELS

-outer circle(s)

THE ATOM

3 subatomic particles

(small pieces of the atom)

In the nucleus:

1. protons

2. neutrons

In the energy levels:

3. electrons

THE ATOM

A substance containing only one type of atom

is:

ELEMENT

THE ELEMENTCARBON ATOM

All known elements are organized in the periodic table.

The periodic table tells you information about

each element

PERIODIC TABLE

Information about elements

Atomic Number-

number of protons in the atom

Chemical Symbol

Atomic Mass-

number of protons and neutrons

Elements are not charged, therefore electrons always equal protons.

Find the following

If the atomic number for H is 1:

How many protons in H?

If the atomic mass of H is 1:

How many neutrons in H?

How many electrons?

Find the followingThe atomic number for O is 8.

How many protons in O?How many electrons in O?

The atomic mass of O is 16.How many neutrons in O?

Draw an Oxygen atom. Show the number of protons and neutrons in the nucleus and the electrons in the energy level.

Draw Nitrogen Draw Carbon

Nitrogen atomic number: 7 atomic mass: 14 Carbon atomic number 6 atomic mass: 12

Molecules 2 or more atoms

held together by chemical bonds

A substance containing two different types of atoms

is:

COMPOUND

All compounds are molecules but not all molecules are

compounds

THE COMPOUNDCARBON ATOM

OXYGEN ATOM

What compound is this?

How many elements in each of the molecules below?

How many atoms in each?

CO2 - carbon dioxide

H2O - water

C6H12O6 - sugar (glucose)

NaCl - salt

O2 - oxygen (usable)

BondingIONIC BOND One atom gives

an electron to another- this causes a charge in the atom

Charged atoms are called ions.

Bonding

Atoms share electrons in order to fill the

last energy level of each

“co-” means shareStrong Bonds!

COVALENT BOND

How many bonds can these make?

Hydrogen Oxygen Nitrogen Carbon

*How many electrons are needed to fill the outer energy level?

Bonds these make

Hydrogen - 1 Oxygen - 2 Nitrogen - 3 Carbon - 4

Chemical Bonds: Hydrogen

Weak bond formed from the unequal sharing of electrons Slightly positive, slightly

negative ends Importance to biology:

critical to water’s properties, holds DNA

together

wh

Chemical Reactions

Synthesis Make a compound Ex: Photosynthesis

Decomposition Break down a compound Ex: Cellular Respiration

Both reactions important to biology: metabolism

Chemical reactions are written like simple addition problems.

H2 O3 H2 O + O2

H2 O3 H2 O + O2

Reactants (inputs): what goes in to the reaction

Products (outputs): what comes out of the reaction

The body is factory of chemicals

Bonding takes place when chemicals react This is called a chemical reaction