AP Biology Unit 1: Matter and Chemical Bonding

The basic or smallest unit of all matter

Atom

The smallest particle of a substance that still retains the properties of that substance

Atom

90% of the mass of a living organism is composed of what four elements

Carbon, Oxygen, Hydrogen, and Nitrogen

The atoms in a compound are held together by ___________

Chemical bonds

The chemical combination of two or more elements in definite proportions

Compound

Which of the three subatomic particles is involved in the bonding between two atoms

Electrons

A pure substance consisting of all the same type of atom

Element

Atoms of the same element that have different numbers of neutrons

Isotopes

This type of bond is formed when electrons are shared EQUALLY between two atoms

Non-polar Covalent Bond

What type of bond is formed when 2 atoms share electrons UNEQUALLY (positive on one end, negative on the other)

Polar Covalent Bond

Name the 3 subatomic particles that make up an atom. Name their charge.

Protons - positive Electrons - negative neutrons - no charge

List two practical uses of radioactive isotopes

They are used to determine the ages of rocks and fossils. Certain radioactive isotopes are used to treat cancer. Radioactive isotopes are used to kill the bacteria that cause food spoilage. They can be used as "tracers" to follow the movement of substances through the body.

What are the two main types of bonds

covalent and ionic

What type of bond is formed when two atoms share electrons

covalent bond

What name is given to an atom that has lost or gained electrons

ion

What type of bond is formed when electrons are transferred from one atom to another

ionic bond

What charge will an atom have if it gains an electron

negative

When electrons are shared unequally between two atoms, the atom that spends more time with the electron will have a _________ charge, and the atom that spends less time with the electron will have a ____________ charge

negative, positive

What charge will an atom have if it loses an electron

positive

The three types of iodine, iodine-127, -129, and -135, have the same number of __________, but they have different numbers of ____________.

protons, neutrons

Isotopes whose nuclei are unstable and break down at a constant rate over time are said to be...

radioactive