MCAT Terms

Question 1

Atom

Answer 1

Tiny particles that compose all mass

Question 2

Nucleas

Answer 2

The center of an atom composed of protons and neutrons surrounded by electrons. Radius 10-4 angstroms.

Question 3

Angstrom

Answer 3

1 angstrom = 10^-10 meters

Question 4

Nucleons

Answer 4

Overarching name for protons and neutrons

Question 5

Atomic Radius

Answer 5

Distance between the nucleus and electrons, approximately 1-3 angstroms

Question 6

Electron

Answer 6

Negatively charged non-nucleon component of an atom

Question 7

Electronic Charge

Answer 7

The charge on one electron or one neutron. 1 e is equal to 1.6 x 10^-19

Question 8

Element

Answer 8

The essential building block of all matter that cannot be broken down into simpler substances by chemical means

Question 9

Mass Number

Answer 9

The mass of protons and neutrons within an atom. The top number on the left of an elements symbol in the periodic table. Changes with the isotope.

Question 10

Atomic Number

Answer 10

The weight of only the protons in the nucleus. The bottom number on the elemental symbol in the periodic table. Does not change with the isotope.

Question 11

Isotopes

Answer 11

Two or more atoms of the same element that contain different numbers of neutrons.

Question 12

Nuclide

Answer 12

A specific isotope

Question 13

Atomic Weight

Answer 13

Also known as molar mass, average weight of all the different isotopes of an element. The one it is closest to is the most prevalent.

Question 14

Mole

Answer 14

A mole of carbon 12 is the number of carbon atoms in twelve grams of carbon. This is given by avogadro’s number.

Question 15

Avogadro’s Number

Answer 15

6.022 x 10^23

Question 16

Moles = ?

Answer 16

grams / atomic or molecular weight

Question 17

The periodic table

Answer 17

A way of organizing elements which lists elements from left to right in order of atomic number. Rows are called periods, columns are called families.

Question 18

Period (Chemistry)

Answer 18

Rows on the periodic table

Question 19

Group or Family (Chemistry)

Answer 19

Columns on the periodic table

Question 20

Metals

Answer 20

Large atoms which tend to lose electrons to form positive ions or positive oxidation states.

Question 21

Properties of Metals

Answer 21

1) Ductile (Easily Stretched)
2) Malleable (Easily Flattened)
3) Thermal and Electrical Conductivity
4) Lustrous

Question 22

Non-Metals

Answer 22

Have diverse appearances and chemical behaviors. Tend to form negative ions. Typically have lower melting points than metals.

Question 23

Alkali Metals

Answer 23

The first group (1A) of the periodic table. Easily form 1+ cations. Low melting point and low density metals. React with hydrogens to form hydrides. React exothermically with water.

Question 24

Alkaline Earth Metals

Answer 24

The second group (2A) of the periodic table. Easily form 2+ cations. Less reactive, more dense, higher melting point, and harder than alkali metals. Heavier ones are more dense than lighter ones.

Question 25

Group 4A Elements

Answer 25

The fourth A group on the periodic table. Can easily form four covalent bonds. Can form two pi bonds to form double or triple bonds. Can form two additional bonds with lewis bases.

Question 26

Halogens

Answer 26

Radioactively stable group 7A elements. Flourine, chlorine, bromine, and iodine. All are diatomic gases at room temperature except bromine.

Question 27

Noble Gases

Answer 27

Also known as inert gases. The group 8A elements. Non reactive. Found in nature as isolated atoms.

Question 28

Effective Nuclear Charge

Answer 28

The amount of nuclear charge experience by the second electron present in an atom. Zeff is the result of electron shielding.

Question 29

Periodic Trends

Answer 29

Totalities of predictions made by coulombs law as a result of Zeff and atomic radius.

Question 30

Ionization Energy

Answer 30

The energy needed to detach an electron from the nucleus. Increases from left to right and from bottom to top.

Question 31

Second Ionization Energy

Answer 31

The energy required for the removal of the second electron from the same atom.

Question 32

Electronegativity

Answer 32

The tendency of an atom to attract an electron in a bond it shares with another atom. Increases from left to right and from bottom to top.

Question 33

Electron Affinity

Answer 33

The willingness of an atom to accept an additional electron. Increases from left to right and from bottom to top.

Question 34

Metallic Character

Answer 34

Increases from right to left and from bottom to top.

Question 35

Trends increasing from left to right and from bottom to top.

Answer 35

Energy of Ionization, Electron Affinity, and Electronegativity

Question 36

Trends increasing from right to left and from top to bottom

Answer 36

Atomic radius and metallic character