CHEMISTRY OF LIFE

Question 1

is any substance that
occupies space and has mass.

Answer 1

Matter

Question 2

are unique forms of
matter with specific chemical and
physical properties that cannot be
broken down into smaller
substances by ordinary chemical
reactions.

Answer 2

Elements

Question 3

how many elements are there?

Answer 3

118

Question 4

how many elemts only occur naturally

Answer 4

92

Question 5

what are the four elements common to all living organisms

Answer 5

• oxygen (O),
• carbon (C),
• hydrogen (H), and
• nitrogen (N).

Question 6

is the smallest unit of matter that retains all
of the chemical properties of an element.

Answer 6

atom

Question 7

All atoms contain

Answer 7

protons, electrons, and neutrons.

Question 8

is a positively charged particle
that resides in the nucleus of an atom and
has a mass of 1 and a charge of +1.

Answer 8

proton

Question 9

is a negatively charged particle
that travels in the space around the
nucleus. It has a negligible mass and has a
charge of –1.

Answer 9

electron

Question 10

like protons, reside in the
nucleus of an atom. They have a mass of 1
and no charge.

Answer 10

Neutrons

Question 11

charges balance each other in a
neutral atom, which has a net zero charge.

Answer 11

Neutrons

Question 12

The ——— of an element is equal to the
number of protons that element contains.

Answer 12

atomic number

Question 13

it is the number of protons plus the
number of neutrons of that element.

Answer 13

mass number

Question 14

the —- of an atom is equal to the number of protons and neutrons of
that atom.

Answer 14

mass of an atom

Question 15

These numbers provide information about the elements
and how they will react when combined.

Answer 15

atomic number and atomic mass

Question 16

A chart of the elements that includes the atomic number and relative atomic mass of each element.

Answer 16

The Periodic
Table

Question 17

provides key
information about the
properties of elements.

Answer 17

The Periodic
Table

Question 18

shows how the electrons in each element are organized and provides important details about how atoms will react with each other to form molecules.

Answer 18

The Periodic
Table

Question 19

are different forms of the same element that have the
same number of protons, but a different number of neutrons.

Answer 19

Isotopes

Question 20

the most common isotope of carbon, contains six protons and
six neutrons. Therefore, it has a mass number of 12 (six protons and six neutrons) and an atomic number of 6 (which makes it carbon).

Answer 20

Carbon-12

Question 21

contains six protons and eight neutrons. Therefore, it has a
mass number of 14 (six protons and eight neutrons) and an atomic number of 6, meaning it is still the element carbon.

Answer 21

Carbon-14

Question 22

are isotopes that are Unstable and will lose
protons, other subatomic particles, or energy to form more
stable elements.

Answer 22

Radioactive isotopes or radioisotopes

Question 23

The closest shell can hold up to how many electrons?

Answer 23

two electrons

Question 24

The second and third energy levels can hold up to how many electrons

Answer 24

8 electrons

Question 25

are interactions between two or more of the same or
different elements that result in the formation of molecules.

Answer 25

Chemical bonds

Question 26

The tendency of atoms with low atomic numbers
(Elements with atomic numbers up to 20 except Hydrogen and Helium) to prefer to have eight electrons in the valence shell

Answer 26

The octet rule:

Question 27

It is when some atoms are more stable when they gain or lose an electron(s) and form ions.

Answer 27

Ionic Bonds

Question 28

are positive ions that are formed by losing electrons.

Answer 28

Cations

Question 29

Negative ions are formed by gaining electrons and are called

Answer 29

anions

Question 30

This movement of electrons from one element to another is
referred to as electron transfer.

Answer 30

Ionic Bonds

Question 31

Another way the octet rule can be satisfied is by the sharing of
electrons between atoms to form

Answer 31

Covalent Bonds

Question 32

These bonds are stronger and much more common than ionic
bonds in the molecules of living organisms.

Answer 32

Covalent Bonds

Question 33

is the
most abundant gas in the atmosphere.

Answer 33

N2

Question 34

The formation of water molecules provides an example of

Answer 34

covalent
bonding

Question 35

what are the two types of covalent bond

Answer 35

polar and nonpolar

Question 36

form between two atoms of the same element or
between different elements that share the electrons equally.

Answer 36

Nonpolar covalent bonds

Question 37

it is when a covalent bond when the electrons shared by the atoms spend more time closer to one nucleus than to the other nucleus.

Answer 37

polar bond

Question 38

the unequal distribution of electrons between the different nuclei, a slightly positive (δ+) or slightly negative (δ–) charge develops.

Answer 38

polar bond

Question 39

this bond provide many of
the critical, life-sustaining properties of water and
also stabilize the structures of proteins and DNA,
the building block of cells.

Answer 39

Hydrogen Bonds

Question 40

Weaker bonds can also form between molecules.
Two weak bonds that occur frequently are:

Answer 40

• hydrogen bonds and
• van der Waals interactions.