the chemical context of life (2)

Question 1

anions

Answer 1

negatively charged ions

Question 2

atom

Answer 2

the smallest unit of matter that still retains the properties of an element

Question 3

atomic mass

Answer 3

the atoms total mass, can be approximated by the mass number

Question 4

atomic number

Answer 4

number of protons in the nucleus

Question 5

cations

Answer 5

positively charged ions

Question 6

chemical bonds

Answer 6

when atoms share electrons keeping them close together

Question 7

chemical equilibrium

Answer 7

when a forward and reverse reaction occurs at the same rate

Question 8

chemical reactions

Answer 8

when a bond is made or broken. These are reversible-meaning the reaction can proceed in the forward or reverse direction

Question 9

compound

Answer 9

a substance consisting of two or more elements in a fixed ratio

Question 10

covalent bond

Answer 10

sharing a pair of valence electrons by two atoms

Question 11

daltons

Answer 11

the unit of measure for an atom’s mass. Calculated by neutron + proton mass. Electrons have a negligible amount of mass, and therefore do not contribute to the calculation

Question 12

double bond

Answer 12

the sharing of two pairs of valence electrons

Question 13

electronegativity

Answer 13

an atom’s attraction for the electrons in a covalent bond

Question 14

electrons

Answer 14

a subatomic particle with a negative charge located in electron shells also called the electron cloud

Question 15

electron shells

Answer 15

an energy level of electrons at a characteristic average distance from the nucleus of an atom

Question 16

electron cloud

Answer 16

negative charge around the nucleus

Question 17

element

Answer 17

a substance that cannot be broken down to other substances

Question 18

emergent properties

Answer 18

characteristics specific to an element

Question 19

energy

Answer 19

the capacity to cause change

Question 20

essential elements

Answer 20

elements that are required for life

Question 21

half-life

Answer 21

the time it takes for a radioactive isotope (the parent isotope) to decay half way to the daughter isotope (ie. for the parent isotope to reach 50% concentration)

Question 22

hydrogen bonds

Answer 22

when a hydrogen atom covalently bonded to one electronegative atom is also attracted to another electronegative atom. The binds typically incorporate oxygen (o), nitrogen (n), fluorine (f), and sulfur (s)

Question 23

ionic bond

Answer 23

when a cation and anion are together

Question 24

ionic compounds or salts

Answer 24

compounds formed by ionic bonds

Question 25

ions

Answer 25

when an atom strips an electron from its bonding partner

Question 26

isotopes

Answer 26

two atoms of an element with the same number of protons, but a different number of neutrons

Question 27

mass number

Answer 27

the sum of protons and neutrons

Question 28

matter

Answer 28

anything that takes up space and has mass

Question 29

molecule

Answer 29

consists of two or more atoms held together by covalent bonds (two atoms that may or may not be the same)

Question 30

neutrons

Answer 30

a subatomic particle with no charge that is located in the atomic nucleus

Question 31

atomic nucleus

Answer 31

an atom's dense central core, containing protons and neutrons

Question 32

non-polar covalent bond

Answer 32

the atoms share electrons equally

Question 33

orbital

Answer 33

the three-dimensional space where an electron is found 90% of the time

Question 34

polar covalent bond

Answer 34

one atom is more electronegative that the other and electrons are not shared equally. (ie, the electron which has a negative charge is going to spend more time towards the more electronegative atom)

Question 35

potential energy

Answer 35

the energy that matter possesses because of its location or structure

Question 36

products

Answer 36

the resulting molecules from a chemical reaction

Question 37

protons

Answer 37

subatomic particle that has a positive charge located in the atomic nucleus. Protons are responsible for the identity of an atom (ie. carbon always has 6 protons)

Question 38

radioactive isotopes

Answer 38

isotopes that will decay spontaneously giving off particles and energy

Question 39

radiometric dating

Answer 39

using radioactive isotopes to measure how old something is by comparing the parent isotope concentration to the daughter concentration

Question 40

reactants

Answer 40

starting molecules of a chemical reaction

Question 41

single bond

Answer 41

the sharing of one pair of valence electrons

Question 42

subatomic particles

Answer 42

the components of an atom

Question 43

trace elements

Answer 43

elements that are only required in small quantities for life

Question 44

valence

Answer 44

the atoms bonding capacity (ie. how many electrons are available for bonding)

Question 45

valence shells

Answer 45

the outermost shell that houses the valence electrons

Question 46

van der waals interactions

Answer 46

when electrons are not evenly distributed and they happen to attract another molecule. Individually these are very weak interactions, but when added together can be very strong