Bio powerpoint 2

Question 1

all matter is made up of

Answer 1

atoms

Question 2

what is at the core of a nucleus

Answer 2

protons
neutrons

Question 3

what orbits a nucleus

Answer 3

electrons

Question 4

atomic number:

Answer 4

number of protons in nucleus

Question 5

mass number:

Answer 5

number of protons plus neutrons in nucleus

Question 6

where are electrons most likely to be found

Answer 6

orbitals

Question 7

what are orbitals

Answer 7

three dimensional volumes of space
(electron shells) that are around an atom

Question 8

electron energy levels:

Answer 8

closer to nucleus = has more energy

further from nucleus = requires more energy

Question 9

what are ions

Answer 9

atoms that have gained or lost one or more electrons

Question 10

what are isotopes

Answer 10

atoms that have same number of protons,
different number of neutrons

Question 11

what is radioactive decay

Answer 11

when isotopes are unstable and break up into particles with lower atomic numbers

Question 12

uses for radioactive isotopes:

Answer 12

dating fossils
medical procedures

Question 13

short lived isotopes:

Answer 13

decay rapidly
can be used as tracers in medical studies

Question 14

what is a molecule

Answer 14

a group of atoms held together by energy in the form of a chemical bond

Question 15

3 principle types of chemical bonds:

Answer 15

ionic
covalent
hydrogen

Question 16

ionic bonds involve:

Answer 16

attraction of opposite electrical charges
(stable as crystals)

Question 17

what creates a polar molecule

Answer 17

some atoms attracting shared electrons of a covalent bond better
(tiny negative & positive charges)

Question 18

covalent bonds:

Answer 18

form between two atoms when they share electrons
(very strong)

Question 19

polar covalent bonds:

Answer 19

shared electrons of covalent bond spend more time with an atom

Question 20

hydrogen bonds:

Answer 20

weak electrical attractions between positive end of polar molecule, and negative end of another

Question 21

water molecules are:

Answer 21

polar and can form hydrogen bonds with each other

Question 22

properties of water

Answer 22

stores heat
forms ice
evaporates

Question 23

cohesion:

Answer 23

one water molecule attracted to another

Question 24

adhesion:

Answer 24

polar molecules other than water sticking to water molecule

Question 25

water molecules tend to

Answer 25

form the maximum number of hydrogen bonds
(very polar)

Question 26

hydrophilic molecules:

Answer 26

are attracted to water and dissolve easily in it
(also polar)

Question 27

hydrophobic molecules:

Answer 27

repelled by water and do not dissolve
(non polar)

Question 28

water ionizing is:

Answer 28

covalent bond within water molecule breaking suddenly

Question 29

the pH scale is:

Answer 29

logarithmic

Question 30

logarithmic is:

Answer 30

a difference of 1 unit represents 10 fold change in hydrogen ion concentration

Question 31

acid:
(below 7 pH

Answer 31

any substance that dissociates in water and increases in H+

Question 32

Base:
(above 7 pH)

Answer 32

any substance that combines with H+ when dissolved in water

Question 33

organisms use ________ to minimize ph disturbances

Answer 33

buffers

Question 34

what is a buffer

Answer 34

a chemical substance that takes up or releases hydrogen ions