Chapter 2 - The Nature of Molecules

Question 1

atoms

Answer 1

Smallest element of a substance that retains the characters of the substance.

Question 2

molecules

Answer 2

Groups of atoms, held by bonds

Question 3

electrons

Answer 3

Negatively charged particles. Equals the number of protons in atoms.

Question 4

protons

Answer 4

Positively charged particles in the center of an atom. Equals the number of protons in atoms.
(Determines the atomic number.)

Question 5

neutrons

Answer 5

Neutral particles in the atom’s nucleus.

With the protons, determines the atomic weight/mass.

Question 6

ions

Answer 6

Charged atoms, that have gained or lost one or more electrons.
(Cations - positively charged, lost electron(s)
Anions - negatively charged, gained electron(s))

Question 7

mass

Answer 7

Amount of a substance, a universal constant, independent of gravitational pull (weight)

Question 8

Dalton

Answer 8

Discovered the fixed ratio of elements in substances (with the aid of electrolysis), such as H2O, CO2, etc.
(Worked with elements vs. compounds - a chemist, not an alchemist)

Question 9

isotope

Answer 9

Atoms of the same elements that have different atomic masses due to differing numbers of neutrons.

Question 10

oxidation

Answer 10

Loss of an electron

Transferred to another atom while still retaining the energy level in the atom

Question 11

reduction

Answer 11

Gain of an electron

Question 12

ionic bond

Answer 12

Formed by the attraction of oppositely charged ions

Question 13

covalent bond

Answer 13

Formed when ions share 2 or more valence electrons

Strength depends on the number of electron pairs shared by the atoms

Question 14

hydrogen bond

Answer 14

Weak attractions between the partially negative oxygen of one water molecule and the partially positive hydrogen of a different water molecule.
(Most important property of water.)

Question 15

single bond

Answer 15

1 pair (2 electrons) shared between atoms in a covalent bond

Question 16

double bond

Answer 16

2 pairs (4 electrons) shared between atoms in a covalent bond

Question 17

polar

Answer 17

In covalent bonds, an unequal sharing of electrons

Question 18

non-polar

Answer 18

In covalent bonds, an equal sharing of electrons

Question 19

hydrophilic

Answer 19

“water loving”

Question 20

hydrophobic

Answer 20

“water fearing”

Water causes hydrophobic molecules aggregate or assume specific shapes.

Question 21

nucleus

Answer 21

The center of an atom, with protons and neutrons

Question 22

orbital

Answer 22

Areas where electrons are found. Only 2 electrons per orbital. Those furthest from the nucleus have the greatest energy.

Question 23

atomic number

Answer 23

Count of protons in an atom

Question 24

atomic mass

Answer 24

Sum of protons and neutrons in an atom.

Question 25

valence

Answer 25

Electrons in the outermost energy level of an atom.

Question 26

pH

Answer 26

A measure of the amount of H+ ions in a substance

Question 27

acid

Answer 27

Lower than 7 on the pH scale (greater concentration of H+ ions)

Question 28

base

Answer 28

Higher than 7 on pH scale (lower concentrations of H+ ions)