U1 C2: chemical context of life

Question 1

matter is

Answer 1

anything that takes up space and has mass

Question 2

elements

Answer 2

substances that cannot be broken down to other substances by chemical reactions

Question 3

compound

Answer 3

a substance made up of 2 or more elements in a ratio

Question 4

compounds have different characteristics than their elements

Answer 4

emergent

Question 5

how many elements are there

Answer 5

92

Question 6

essential elements

Answer 6

20-25% of elements in the periodic table are needed for an organism to live

Question 7

trace elements

Answer 7

elements required for living things in very small quantities

Question 8

atom

Answer 8

smallest unit of an element still maintaining the original properties

Question 9

protons

Answer 9

positively charged subatomic particle

Question 10

electrons

Answer 10

negatively charged

Question 11

neutrons

Answer 11

neutral

Question 12

mass of an atom is measured in..

Answer 12

daltons or amu

Question 13

neutrons and protons are

Answer 13

1 dalton/amu

Question 14

atomic number

Answer 14

number of protons in the atom

- can also be the number of neutrons if the atom is neutrally charged

Question 15

mass number

Answer 15

number of neutrons and protons

Question 16

atomic mass

Answer 16

total mass of an atom

Question 17

isotopes

Answer 17

atoms that have more NEUTRONS than others of the same element

Question 18

all isotopes behave how in a chemical reaction?

Answer 18

similarly

Question 19

orbitals

Answer 19

the 3-D space where a given electron spends 90& of its time

Question 20

is it possible to know the exact location of an electron at a given moment?

Answer 20

nope

Question 21

concentric-circle diagrams are…

Answer 21

2-D visualisations of atoms involving electrons orbiting the nucleus in concentric paths

Question 22

what is the advantage of concentric-circle diagrams?

Answer 22

it’s convenient to work with and understand the chemistry of an atom, particularly involving its electrons

Question 23

what is the disadvantage of concentric-circle diagrams?

Answer 23

concentric orbits only represent average distance between electron and nucleus; not representative of an atom’s actual structure

Question 24

electron orbitals constitute …

Answer 24

shells

Question 25

a single orbital can have how many electrons?

Answer 25

2 at most

Question 26

s orbitals are...

Answer 26

spherical

Question 27

p orbitals...

Answer 27

dumbell -shaped

Question 28

first shell is comprised of ...

Answer 28

1s (one s orbital)

Question 29

second shell is comprised of ...

Answer 29

2s (one s orbital), 2p (three p orbitals)

Question 30

electrons in different orbitals share ... but differ in ...

Answer 30

the amount of energy (nearly) ... move in different volumes of space

Question 31

what causes the reactivity of a given atom?

Answer 31

the presence (or lack thereof) of one or more unpaired electrons in their orbitals

Question 32

the electrons that tend to interact in atoms are the ... such that the atom's ... are completed

Answer 32

unpaired electrons ... valence shells

Question 33

chemical bonds

Answer 33

the interactions between atoms with generally incomplete valence shells such that valence electrons are transferred or shared in order to complete valence shells

Question 34

strong bonds

Answer 34

covalent bonds, ionic bonds (dry)

Question 35

weak bonds

Answer 35

ionic bounds (aqueous, solutions), hydrogen bonds, van der waals interactions

Question 36

covalent bonds

Answer 36

chemical bond that involved the sharing of a pair of valence electrons (unpaired valence electrons approach each other and form a shared covalent bond with each electron being attracted to the other atom's nucleus)