Biology Module 3- The Chemistry of Life

What is the atomic theory?

all matter is composed of small, indestructible particles called atoms

Elements

A molecule composed of one kind of atom; cannot be broken into simpler units by chemical reactions.

Compounds

2 or more elements chemically combined

What elements are important to life?

carbon, hydrogen, oxygen, nitrogen

Ernest Rutherford

discovered the nucleus using the gold foil experiment

Structure of atom

protons and nuetrons are located in the nucleus, electrons are distributed about the nuclus to make the atom

Protons

Positively charged particles

Neutrons

the particles of the nucleus that have no charge

Electrons

Negatively charged particles

Why do the basic chemical properties of an element depend on the structure of its atoms (particularly valence electrons)?

Because valence electrons are the ones involved in chemical bonding

Covalent bonds

Bonds created by sharing electrons with other atoms.

covalent polar bonds

unequal sharing of electrons

Covalent Nonpolar Bonds

equal sharing of electrons

ionic bonds

A chemical bond resulting from the attraction between oppositely charged ions.

Hydrogen bonds

weak attraction between a hydrogen atom and another atom

Isotope

Atoms of the same element that have different numbers of neutrons

Ions

Charged atoms

molecular formula

shows the types and numbers of atoms combined in a single molecule of a molecular compound

structural formula

a formula that shows the arrangement of atoms in the molecule of a compound.