Question 1

Alchemy:

Accepted Answer

Early study of materials and their transformations that preceded modern chemistry.

Question 2

Alkali metals:

Accepted Answer

Group 1 metals, excluding hydrogen; commonly form +1 ions.

Question 3

Alkaline earth metals:

Accepted Answer

vGroup 2 elements; commonly form +2 ions.

Question 4

Alpha particle:

Accepted Answer

A helium-4 nucleus containing two protons and two neutrons, with charge +2.

Question 5

Anion:

Accepted Answer

A negatively charged ion.

Question 6

Atomic number:

Accepted Answer

Number of protons in an atom’s nucleus.

Question 7

Average atomic mass:

Accepted Answer

Abundance-weighted mean of an element’s isotope masses. (Average atomic mass = sum of (isotope mass × fractional

abundance) for all isotopes.

Question 8

Becquerel:

Accepted Answer

Scientist who discovered spontaneous radioactivity in uranium compounds.

Question 9

Ben Franklin:

Accepted Answer

Investigator of electricity who introduced the positive and negative charge convention.

Question 10

Beta Particle:

Accepted Answer

An electron emitted in beta-minus decay, or a positron in beta-plus decay; the

usual introductory example is the electron, charge −1.

Question 11

Cathode Ray Tube Experiments:

Accepted Answer

Experiments with electron beams that established the
existence and negative charge of electrons and measured their
charge-to-mass ratio.

Question 12

Cation:

Accepted Answer

+ positive charged ion

Question 13

Chalcogens:

Accepted Answer

Group 16 elements, with six valence electrons in neutral main-group atoms.

Question 14

Charge:

Accepted Answer

Electrical property that produces attraction or repulsion; a monatomic ion’s charge
equals protons minus electrons in elementary-charge units.

Question 15

Coinage metals:

Accepted Answer

Traditionally copper, silver, and gold in group 11.

Question 16

Dalton:

Accepted Answer

Scientist who developed an early modern atomic theory and the law of multiple
proportions.

Question 17

Democritus:

Accepted Answer

Ancient thinker who proposed that matter consists of atoms and empty space.

Question 18

Electron:

Accepted Answer

Negatively charged subatomic particle outside the nucleus; its mass is about 1/1836 of
a proton’s mass.

Question 19

Electrostatic forces:

Accepted Answer

Attractions between opposite charges and repulsions between like charges.

Question 20

Energy levels:

Accepted Answer

Allowed, discrete electron energies in an atom.

Question 21

Fractional abundance:

Accepted Answer

Fraction of an element’s atoms belonging to an isotope; all isotope fractions total 1.

Question 22

Covalent Bond:

Accepted Answer

A covalent bond is a chemical link formed when two nonmetal atoms share one or more pairs of electrons

Question 23

Gamma radiation:

Accepted Answer

High-energy electromagnetic radiation emitted by a nucleus; it has no charge or rest mass.

Question 24

Gold Foil Experiment:

Accepted Answer

Alpha-particle scattering experiment supporting a small, dense, positively charged nucleus and mostly empty atomic space.

Question 25

Group / family:

Accepted Answer

Vertical column of the periodic table.

Question 26

Halogens:

Accepted Answer

Group 17 elements, with seven valence electrons; commonly form −1 ions.

Question 27

Inner transition metals:

Accepted Answer

The lanthanide and actinide series, associated with filling f subshells.

Question 28

Ion:

Accepted Answer

An atom or group of atoms with a net electric charge.

Question 29

Isotope:

Accepted Answer

Atoms of the same element with different neutron numbers.

Question 30

Isotope name:

Accepted Answer

Element name followed by mass number, such as carbon-14.

Question 31

Law of Conservation of Mass:

Accepted Answer

Total mass remains constant during a chemical reaction in a
closed system.

Question 32

Law of Definite Composition:

Accepted Answer

A pure compound has a fixed elemental composition by mass.

Question 33

Law of Multiple Proportions:

Accepted Answer

When two elements form different compounds, the masses of one  combining with a fixed mass of the other are in small whole-
number ratios.

Question 34

Marie Curie:

Accepted Answer

Radioactivity researcher who helped discover polonium and radium and later isolated radium. Coined the term radioactivity.

Question 35

Mass number:

Accepted Answer

Total number of protons and neutrons in a nucleus.

Question 36

Mass spectrometer:

Accepted Answer

Instrument that separates and detects ions according to mass-to-charge ratio.

Question 37

Metalloids:

Accepted Answer

Elements with properties intermediate between metals and nonmetals; many are semiconductors.

Question 38

Metals:

Accepted Answer

Elements generally characterized by conductivity, luster, malleability, and a tendency to form positive ions.

Question 39

Millikan:

Accepted Answer

Scientist whose oil-drop experiment measured the elementary electric charge.

Question 40

Multivalent:

Accepted Answer

Able to exhibit more than one oxidation state; here, commonly forming monatomic ions with different positive charges.

Question 41

oxidation state

Accepted Answer

the hypothetical charge an atom would have if all of its bonds to other atoms were completely ionic

Question 42

Neutron:

Accepted Answer

Uncharged nuclear particle with mass approximately 1 u.

Question 43

Noble Gases:

Accepted Answer

Group 18 elements with filled outer electron shells and generally low reactivity.

Question 44

Nonmetals:

Accepted Answer

Elements generally lacking metallic properties; often gain or share electrons in bonding.

Question 45

Nuclear model:

Accepted Answer

Atomic model with a small, dense nucleus and electrons outside it.

Question 46

Nuclear symbol:

Accepted Answer

Element symbol with mass number at upper left, atomic number at lower left, and ion charge at upper right when needed.

Question 47

Nucleus:

Accepted Answer

Small, dense atomic center containing protons and neutrons and nearly all the atom’s mass.

Question 48

Octet rule:

Accepted Answer

Tendency of many main-group atoms to gain, lose, or share electrons to achieve eight outer-shell electrons; exceptions occur.

Question 49

Oil drop experiment:

Accepted Answer

Charged-drop experiment demonstrating quantized charge and measuring the electron’s charge magnitude.

Question 50

Oil Rig:

Accepted Answer

Mnemonic: Oxidation Is Loss; Reduction Is Gain of electrons.

Question 51

Oxidation:

Accepted Answer

Loss of electrons; increase in oxidation number.

Question 52

Oxidation number:

Accepted Answer

Represents the number of electrons a neutral atom will likely lose or gain in a chemical reaction.

Question 53

Period / series:

Accepted Answer

Horizontal row of the periodic table.

Question 54

Plum Pudding Model:

Accepted Answer

Thomson’s model of electrons embedded in diffuse positive charge.

Question 55

Pnictogens:

Accepted Answer

Group 15 elements, with five valence electrons.

Question 56

Proton:

Accepted Answer

Nuclear particle with charge +1 and mass approximately 1 u.

Question 57

Proust:

Accepted Answer

Scientist associated with the law of definite composition.

Question 58

Reduction:

Accepted Answer

Gain of electrons; decrease in oxidation number.

Question 59

Relative abundance:

Accepted Answer

Here, the percentage of an element’s atoms belonging to a particular isotope.

Question 60

Roentgen:

Accepted Answer

Scientist who discovered X-rays.

Question 61

Rutherford:

Accepted Answer

Scientist who interpreted alpha scattering to propose the nuclear atom.

Question 62

Subatomic particles:

Accepted Answer

Particles smaller than an atom, including protons, neutrons, and electrons.

Question 63

Thomson:

Accepted Answer

Discovered the electron and proposed the plum pudding model.

Question 64

Transition metals:

Accepted Answer

Elements whose atoms or cations have an incomplete d subshell; introductory tables often group the central d-block metals together.

"Know" box contains:
Time elapsed:
Retries:

Stack #4736778