Biology 221 Chapter 2

- Anything that contains mass and occupies space

- Comes in three states: Solid, Liquid, Gas

- The amount of matter in any object

- The smallest functional units of matter

- Two or more atoms bonded together

- A molecule composed of two or more different elements

- A pure substance of only one kind of atom

- Protons (positive +1), Neutrons (neutral 0), and Electrons (negative -1)

- The protons and neutrons are located in the nucleus of an atom. The electrons are surrounding the nucleus in orbitals.

- The overall charge associated with an atom is 0 as long as it is not an ion because there are the same number of electrons as there are protons and the cancel each other out.

- Center of an Atom that contains protons and neutrons

- The region of space surrounding the atomic nucleus in which there is a high probability of finding an electron

- Maximum of two electrons per orbital

- When electrons share the same energy level, shape, and orientation, we say they are in the same orbital

- Within a shell (same "n"), all electrons that share the same "l" (the angular momentum quantum number, or orbital shape) are in the same sub-shell

- s, p, d, f, etc.

- Composed of one or more orbitals

- All electrons that have the same value for "n" (the principle quantum number) are in the same shell

- labeled as, 1, 2, 3, etc. For example: 1s, 2s, 2p

- Capacity to do work of effect change

- Energy of moving matter

- Electrons found in the outermost shell

- Number of protons in an atom

- And the number of electrons (the exception is ions)

- Rows of the periodic table

- Indicate the number of electron shells

- Columns of the periodic table

- Indicate the number of electrons in outer shell

- Indicates an atom's mass relative to the mass of other atoms

- Measured in Daltons Da

One Da

- Contains the same number of atoms for any particular substance as there are in 12 grams of Carbon

- Atoms that differ in the number of neutrons they contain

- They can have smaller or greater masses than the atoms atomic number depending on if they lose or gain neutrons

- The atomic number is an average mass of all the isotopes that exist

- They often have similar chemical properties, but may have very different physical ones

- Inherently unstable isotopes

- radioactive isotope

- They lose energy by emitting subatomic particles and/or radiation until they become stable

- Elements that are found in uncombined form in nature

- Calcium or Phosphorus

- Required in only minute amounts by living organisms for normal growth

- Iron

- Chemical symbols for all of the atoms that are present

- Bonds in which atoms share a pair of electrons

- Strong chemical bonds

- Many atoms are most stable when they have eight electrons in their outermost electron shell

- When electrons share two pairs of electrons

- When electrons share three pairs of electrons

- A measure of an atoms ability to attract electrons in a bond with another atom

- It is low because there is a larger distance between the nucleus and the valence electrons

-Substance that releases hydrogen ions

-pH of 6 or lower is considered an acid

-Substance the binds hydrogen ions

-pH of 8 or higher is considered a base

-log [H]

Amount of heat energy that must be released to change from liquid to solid

Amount of heat energy required to raise the temperature of 1 gram of a a substance 1 degree Celsius.

Amount of heat required to raise temperature on entire object or substance