Bio Chapter 2

Front 1

element

Back 1

types of atom

Front 2

atom

Back 2

fundamental substances that have mass and take up space

Front 3

4 most abundant elements in living things

Back 3

oxygen, hydrogen, carbon, nitrogen

Front 4

proton

Back 4

positively charged subatomic partivcle which is found in the nucleus of the atom

Front 5

neutron

Back 5

subatomic particlle that has mass but no charge - found in nucleus

Front 6

electron

Back 6

negatively charged unit of matter with particle like and wave like properties - found around the nucleus

Front 7

atomic number

Back 7

number of protons in nucleus - defines the element

Front 8

mass number

Back 8

sum of all protons and neutrons in the nucleus

Front 9

periodic table

Back 9

arrangement of elements in a table based on their chemical properties

Front 10

inert elements

Back 10

elements whose electrons are not available for chemical interaction - helium, neon, radon

Front 11

What is uniqe about the elements after #92?

Back 11

they are highly unstable and have only been produced in a lab, not in nature

Front 12

Which subatomic particle is responsible for the bonding capabilities of an element?

Back 12

electrons

Front 13

isotope

Back 13

an atom that differs in the number of neutrons

Front 14

radioactive decay

Back 14

atoms emits energy as subatomic particles and xrays as its unstable nucleus disintegrates - changes one element into another

Front 15

radioisotope

Back 15

an isotope with an unstable nucleus (too many or too few neutrons)

Front 16

tracers

Back 16

substance with a radioisotope attached that researchers can track after putting it in a cell, multicell body or ecosystem

Front 17

How are radioisotopes used in medicine

Back 17

used in imaging studies in medicine

Front 18

orbital

Back 18

volume of space around the nucleus

Front 19

energy level

Back 19

electron shell - electrons are arranged around the nucleus in energy levels, with the lowest energy closest to the nucleus

Front 20

chemical bonding

Back 20

when electrons swap between atoms

Front 21

molecule

Back 21

2 or more atoms joined in a chemical bond

Front 22

compound

Back 22

molecules that consist of w or more different elements whose proportions never change - eg. H2O

Front 23

mixture

Back 23

2 or more molecules intermingled without chemical bonding

Front 24

chemical equation for photosynthesis

Back 24

12 H2O + 6 CO2 (reactants) + sunlight = 6 O2 + C6H12O6 (glucose) + H2O (products)

Front 25

ion

Back 25

an atom that has a + or - charge formed when atoms gain or lose electrons

Front 26

ionic bond

Back 26

when 2 ions stay close together because they attract eachother - this keeps ions in orderly arrangements

Front 27

covalent bond

Back 27

when atoms share one or more electrons - these bonds are more stable than ionic bonds

Front 28

polar covalent bond

Back 28

forms between atoms of different elements - H2O
(H-O-H) - 2 polar covalent bonds

Front 29

nonpolar covalent bond

Back 29

2 identical atomsshare electrons equally - eg. H2, O2, N2

Front 30

hydrogen bond

Back 30

interaction between a negatively charged atom and hydrogen atom (type of ionic bond) because H side is slightly positive

Front 31

What is the difference between a chemical formula and a structural formula

Back 31

structural - write out each atom showing its bonds eg
H-O-H
chemical - just writes out the number of each type of atom - eg. H2O

Front 32

How are single, double and triple bonds drawn in a structural formula

Back 32

-
=
three lines

Front 33

Why are hydrogen bonds important to life?

Back 33

they are imporant in the function of biological molecules especially water and they also hold the 2 nucleotide strands of DNA together

Front 34

hydrophilic

Back 34

polar molecules - bond easily with water - water liking

Front 35

hydrophobic

Back 35

nonpolar molecules - repel water - water hating

Front 36

temperature

Back 36

measure of molecular motion

Front 37

evaporation

Back 37

heat energy converts liquid to gas

Front 38

solute

Back 38

dissolved substance

Front 39

solvent

Back 39

substance in which something dissolves - water is an excellent solvent for polar molecules

Front 40

cohesion

Back 40

substance showing a capacity to resist breaking when it is stretched

Front 41

water absorbs a good deal of heat energy before it gets measurable hotter. Why is this good for aquatic organisms

Back 41

Water acts as a heat reservoir - its temperature remains relatively stable - eventually heat will increase motion of water molecules but first energy will go into breaking hydrogen bonds

Front 42

Why is ice forming at top of lakes etc. good for aquatic organisms?

Back 42

Ice blanket insulates water beneath it and helps protect aquatic organisms fr om freezing

Front 43

How is cohesion helpful in plants?

Back 43

As H2O molecules evaporate, their cohesion with other H2O molecules results in H2O being pulled up to take the place of the molecules that evaporated

Front 44

pH scale

Back 44

a measure of the relative amount of hydrogen ions in solution

Front 45

acids

Back 45

substances which donate H+ ions when dissolved in water.

Front 46

bases

Back 46

substances which accept H= ions when dissovled in H2O

Front 47

salt

Back 47

any compound that dissolves easily in H2O and releases ions that are not H+ or OH- - eg NaCl

Front 48

buffer systems

Back 48

a weak acid and the base in forms in H2O - the two working as a pair to counteract shifts in pH

Front 49

How many times stronger is a solution with a pH of 2 compared to one with a pH of 4

Back 49

100 x

Front 50

How are antacids used to combat "heartburn"

Back 50

Gastric fluid has a pH of 1 (strong acid) Antacids have pH of 9 (strong base) which neutralizes the acid in the stomach