science chapter 13

Question 1

the organized study of the composition and interactions of matter

Answer 1

chemistry

Question 2

proposed by john dalton, foundation for understanding of matter

Answer 2

atomic theory of matter

Question 3

tiny particles (greek word meaning “not cuttable”)

Answer 3

atoms

Question 4

composed of a single type of atom

Answer 4

elements

Question 5

composed of atoms of two or more elements bonded together

Answer 5

compounds

Question 6

pioneer of the atomic theory

Answer 6

john dalton

Question 7

a unique abbreviation given to each element

Answer 7

chemical symbol

Question 8

atoms are composed of still smaller particles of matter called…

Answer 8

subatomic particles

Question 9

a dense central core in an atom

Answer 9

nucleus

Question 10

the two types of nucleons

Answer 10

protons and neutrons

Question 11

carry a + electric charge

Answer 11

protons

Question 12

electrically neutral, no electric charge

Answer 12

neutron

Question 13

the number of protons in the nucleus

Answer 13

atomic number

Question 14

atoms that are the same element but have different numbers of neutrons

Answer 14

isotopes

Question 15

protons and neutrons are composed of even smaller particles called…

Answer 15

quarks

Question 16

carries a - electric charge

Answer 16

electron

Question 17

each layer that surrounds the nucleus (energy levels)

Answer 17

electron shell

Question 18

an atom that has an electric charge because of losing or gaining electrons

Answer 18

ion

Question 19

the total number of protons and neutrons in the nucleus

Answer 19

mass number

Question 20

the masses of atoms are usually measured in…

Answer 20

atomic mass units (u)

Question 21

the average mass of all the natural isotopes of an element

Answer 21

average atomic mass

Question 22

states that tiny particles like electrons do not absorb or release energy in a smooth flow

Answer 22

quantum theory

Question 23

Niels Bohr, the most familiar model of the atom

Answer 23

bohr model

Question 24

Schrodinger’s hypothesis, or the quantum-mechanical model, explained some puzzling features of atomic structure

Answer 24

wave-mechanical model

Question 25

werner heisenberg stated that it is impossible to measure both the position and velocity of an electron with certainty

Answer 25

Heisenberg uncertainty principle

Question 26

a modified version of the wave-mechanical model

Answer 26

electron-cloud model

Question 27

can hold up to two electrons, the region where electrons move unpredictably

Answer 27

orbitals

Question 28

the overall motion of each electron can be mathematically represented by four...

Answer 28

quantum numbers

Question 29

says that no two electrons in an atom can have the same four quantum numbers

Answer 29

pauli exclusion principle

Question 30

when an atomic nucleus breaks up or undergoes a change, it gives off energy as...

Answer 30

nuclear radiation

Question 31

any substance that is unstable (and thus likely to produce radiation)

Answer 31

radioactive

Question 32

when an atomic nucleus changes from a higher-energy state to a lower-energy state, emitting energy as radiation

Answer 32

radioactive decay

Question 33

the length of time required for one-half of the original substance to decay into a new substance

Answer 33

half-life

Question 34

occurs when an unstable atom ejects a clump of two protons and two neutrons to reach a more stable state

Answer 34

alpha decay

Question 35

the division of a nucleus

Answer 35

nuclear fission

Question 36

domino effect of neutrons splitting other atoms

Answer 36

chain reaction

Question 37

the certain amount of fissionable material present

Answer 37

critical mass

Question 38

a device that initiates an uncontrolled chain reaction

Answer 38

atomic bomb

Question 39

harnesses a type of controlled chain reaction

Answer 39

nuclear reactor

Question 40

the process of combining two nuclei to form a heavier nucleus and thereby releasing energy

Answer 40

nuclear fusion

Question 41

produce more nuclear fuel than they use

Answer 41

breeder reactors

Question 42

uses nuclear fusion to release a tremendous amount of energy

Answer 42

hydrogen bomb

Question 43

the electrons in the valence shell

Answer 43

valence electrons

Question 44

most atoms tend to react to obtain eight electrons in their valence shell

Answer 44

octet rule

Question 45

states that the elements show regular and repeating, or periodic, properties when they are arranged by their increasing atomic numbers

Answer 45

periodic law

Question 46

developed by dmitri mendeleev

Answer 46

periodic table of the elements

Question 47

each row in the table

Answer 47

period

Question 48

each column

Answer 48

group

Question 49

elements n groups 1, 2, and 13-18

Answer 49

main-group elements

Question 50

hard, dense, shiny solids that are good conductors of heat and electricity and have high melting points

Answer 50

metals

Question 51

poor conductors of heat and electricity

Answer 51

nonmetals

Question 52

are all solids that have properties intermediate between metals and nonmetals

Answer 52

semimetals

Question 53

very soft, shiny metals with low melting points; has only one valence electron

Answer 53

alkali metals

Question 54

has two valence electrons; harder, denser and less reactive than the alkali metals but are still softer and less dense than most metals

Answer 54

alkaline earth metals

Question 55

groups 3 to 12; either 1 or 2 electrons in their valence shells; are known for their strength and hardness

Answer 55

transition metals

Question 56

groups 3 to 4; the first 15 are called the lanthanoids, the other 15 are the actinoids; all have 2 electrons in there valence shells and share similiar properties

Answer 56

inner transition metals

Question 57

a basic constituent of all living things and the second most abundant element in the human body

Answer 57

carbon

Question 58

group 17; "salt formers"; they easily combine with alkali and alkaline earth metals to form salts

Answer 58

halogens

Question 59

found in nature in their pure states; no natural compounds of these gases exist

Answer 59

noble gases