Chemistry Review

CHEMISTRY AND LIVING THINGS
Why is chemistry important in biology?
Organisms are made of macro-________.
Macromolecules are made of smaller _______, made of atoms.

Atoms
The Smallest piece of an ________.
________ is made up of atoms
Subatomic Particle Charge Location Proton (+) Nucleus Neutron No charge Nucleus Electron (-) Outside Nucleus

Bohr Model: What makes a nickel different from a piece of gold? VALENCE ELECTRONS: THE OUTER SHELL OF ELECTRONS DETERMINES AN ATOM’S PROPERTIES.

Elements & Periodic Table
Element= A substance made up of __ type of atom
92 natural elements
more than 113 total
Arranged in the Periodic Table based on atomic number and common properties

ISOTOPES
Isotopes= Atoms of the same element that differ in the number of neutrons they contain are known as isotopes
The sum of the protons and neutrons in the nucleus of an atom is called its mass number.

Atomic Number Atomic Mass C 6 12.01 # of Protons P + N * The number of protons equals the number of electrons! P + 6 N 6 E - 6

ISOTOPES
Isotopes are identified by their mass numbers.
For example, carbon has three isotopes—carbon-12, carbon-13, and carbon-14. Each isotope has a different number of neutrons.

ISOTOPES
Because they have the same number of electrons, all isotopes of an element have the same chemical properties.

RADIOACTIVITY
Radioactive Isotopes
Some isotopes are radioactive, meaning that their nuclei are unstable and break down at a constant rate over time.
Although the radiation these isotopes give off can be dangerous, they have important scientific and practical uses.

RADIOACTIVITY
Radioactive isotopes can be used:
to determine the ages of rocks and fossils.
to treat cancer.
to kill bacteria that cause food to spoil.
as labels or “tracers” to follow the movement of substances within an organism.

Chemical Compounds
The same way atoms combine to form elements, elements combine to form compounds .
Compounds have different properties than the elements that make them up.
Water (H 2 0)

Ahh… Nirvana
All atoms want to have a full outer shell
1 st level = 2 electrons
All other shells = 8 electrons
As you move to the right of the periodic table, the elements are getting closer to a full outer shell.

How do atoms combine?
Covalent Bonds
Sharing of electrons
Ionic Bonds
Giving/Taking of electrons
Ions – charged atoms

IONIC BONDS
An atom that loses electrons has a positive charge.
An atom that gains electrons has a negative charge.
These positively and negatively charged atoms are known as ions .

COVALENT BONDS= SHARING

Terms to know
Atom
Proton, Neutron, Electron
Element
Atomic Mass
Atomic Number
Compound
Covalent Bond
Ionic Bond

Chemistry Review

by guestb7edf8

Accessibility

Categories

Upload Details

Usage Rights

Statistics