Chapter 1

Question 1

Based on the principles of chemistry and physics. All living organisms are a collection of atoms and molecules.

Answer 1

Biology

Question 2

What is life?

Answer 2

A structure that 1) reproduces using its own resources, 2) uses energy and produces waste, 3) interacts with the environment.

Question 3

The smallest functional units of matter that form all chemical substances ( CANNOT be further broken down)

Answer 3

Atoms

Question 4

Chemists study atoms and ____________ molecules, which are two or more atoms bonded together.

Answer 4

Molecules

Question 5

Each specific type of atom is a ______________

Answer 5

Chemical ELEMENT

Question 6

Positive charge (+)
found in the atomic nucleus

Answer 6

Protons

Question 7

Neutral
found in the atomic nucleus

Answer 7

Neutrons

Question 8

negative charge (-)
found in orbitals

Answer 8

Electrons

Question 9

If protons and electrons are present in equal numbers, giving the atom _________________

Answer 9

No net charge

Question 10

Electrons travel within regions surrounding the nucleus (orbitals) in which the _______________ of finding the electron is high

Answer 10

Probability

Question 11

are spherical

Answer 11

S Orbitals

Question 12

are propeller or dumbbell shaped

Answer 12

P Orbitals

Question 13

Each orbital can hold only ______________

Answer 13

2 Electrons

Question 14

Atoms with more electrons have orbitals within electrons shells that are at ________________________________ from the center of the nucleus

Answer 14

Greater and greater differences

Question 15

holds one pair of electrons

Answer 15

1st shell (1s)

Question 16

holds one pair of electrons
3 dumbbell-shaped orbitals (2p) - three pairs of electrons
can hold four pairs of electrons = 8 electrons

Answer 16

2 shell (2s, 2p)

Question 17

What distinguishes one element from another?

Answer 17

Number of protons

Question 18

Equals the number of protons
Equal to the number of electrons in the atom so that the net charge is zero.

Answer 18

Atomic number

Question 19

Organized by the atomic number
Rows correspond to the number of electron shells
Columns, from left to right, indicate the number of electrons in the outer shell (the number of valence electrons)

Answer 19

Periodic Table

Question 20

Similar properties of elements within a column occur because they have the same number of electrons in their shells, and therefore they have ______________________________.

Answer 20

Smaller chemical bonding properties

Question 21

Protons and neutrons are ________________.

Answer 21

nearly equal

Question 22

_________________ indicates an atom’s mass relative to the mass of other atoms

Answer 22

Atomic mass scale

Question 23

Atomic mass in relation to the __________________

Answer 23

mass of an electrons

Question 24

Weight is derived from the _________________ on a given mass

Answer 24

gravitational pull

Question 25

A man weighs 154 pounds on Earth - On the moon, he weighs about 25 people - On a neutron star's surface, he would weigh 21 trillion pounds

Answer 25

His mass is the same in all locations

Question 26

Unit of measurement for atomic mass Also known as atomic mass unit (amu) Example: - One Dalton (Da) equals 1/12 the mass of a carbon atom - Carbon has an atomic mass of 12 Daltons

Answer 26

Dalton

Question 27

1 mole of any element contains the same number of atoms Avogadro's number: 6.022 x 10^23

Answer 27

Mole

Question 28

6.022 x 10^23

Answer 28

1 Mole of anything

Question 29

Multiple form sof an element that differ in the number of neutrons

Answer 29

Isotopes

Question 30

_________________ are unstable, emit radiation as they decay Used in medicine for cancer treatment, imaging (PET scan)

Answer 30

Radioisotopes

Question 31

Make up about 95% of the atoms in living organisms

Answer 31

Hydrogen, Oxygen, Carbon, and Nitrogen

Question 32

_________________ occur primarily in water

Answer 32

Hydrogen and Oxygen

Question 33

_____________ found in proteins

Answer 33

Nitrogen

Question 34

____________ is the building block of all living matter

Answer 34

Carbon

Question 35

Contains chemical symbols of the elements in the molecule (C6H12O6) Subscript indicates how many of each atom are present (H2O has two hydrogens, 1 oxygen)

Answer 35

Molecular Formula

Question 36

Any molecule compound of two or more elements H2O; C6H12O6 Properties of a compound can be easily different than the properties of the individual elements in the compound

Answer 36

Compound

Question 37

Electrons are SHARED to fill valence shells Can be polar covalent or non-polar covalent Hydrogen atom from one polar molecule is attracted to an electronegative atom from another molecule

Answer 37

Covalent Bond

Question 38

Electrons are transferred, forming ions that are attached to each other

Answer 38

Ionic Bond

Question 39

Atoms share a pair of electrons Occurs between atoms with unfilled outer electron shell Covalent bonds are STRONG chemical bonds. because the shared electrons behave as if they belong to each atom

Answer 39

Covalent bonds

Question 40

1 pair of electrons H-F

Answer 40

Single bond

Question 41

2 pairs of electrons O=O

Answer 41

Double bond

Question 42

3 pairs of electrons

Answer 42

Triple bond

Question 43

Atoms are stable when their outer shell is full For many atoms, the outer shell is filled with 8 electrons ("the octet rule") An exception is hydrogen, which fills its outer shell with just 2 electrons

Answer 43

Octet Rule

Question 44

What electron number is required to complete the outer shell of Hydrogen?

Answer 44

1

Question 45

What electron number is required to complete the outer shell of Oxygen?

Answer 45

2

Question 46

What electron number is required to complete the outer shell of Nitrogen?

Answer 46

3

Question 47

What electron number is required to complete the outer shell of Carbon?

Answer 47

4

Question 48

- Form between atoms of DIFFERENT ELECTRONEGATIVITY - Shared electrons are more likely to be close to the MORE ELECTRONEGATIVE ATOM - The unequal distribution of electrons creates a POLARITY (difference in electric charge) across the molecule - Examples: O-H and N-H (think Nitrogen)

Answer 48

Polar Covalent Bonds

Question 49

Water has __________________ bonds - Electrons tend to be near the more electronegative OXYGEN atom rather than the less electronegative hydrogen atoms - Water molecule has a PARTIAL NEGATIVE CHARGE (δ-) around the oxygen and a PARTIAL POSITIVE CHARGE (δ+) around the hydrogens

Answer 49

polar covalent

Question 50

- Between atoms with similar electronegativities (attraction to electrons) - Equal sharing of electrons - No change difference across molecule

Answer 50

nonpolar covalent bonds

Question 51

- Weak - An ion is an atom or molecule that has GAINED or LOST one or more electrons - Occurs when a cation binds to an anion by electrostatic attraction Example: NaCl, KCl, CaCl3

Answer 51

ionic bonds

Question 52

Have a net positive charge (+)

Answer 52

cations

Question 53

Have a net negative charge (-)

Answer 53

anions

Question 54

Water molecules form ____ hydrogen bonds

Answer 54

4

Question 55

- The HYDROGEN atom from one polar molecule is attracted to an ELECTRONEGATIVE ATOM of another - Individually, they are weak bonds that form and break easily - Collectively, many H bonds can be strong overall - Holds DNA strands together

Answer 55

hydrogen bonds

Question 56

___________ are molecules that catalyze biologically important chemical reactions - Speeds reaction rate

Answer 56

enzymes

Question 57

- Another type of weak molecular attraction - Arise because electrons are located within orbitals in a random way - A fleeting electrical attraction to other nearby molecules may arise - Collective strength can be quite strong

Answer 57

van der Waals dispersion forces

Question 58

- Atoms combine to form a molecule with three dimensional shape - The shape is determined by the arrangement and number of bonds between atoms - Angles that form between atoms give molecules specific shapes - Covalent bonds are not rigid, and rotation around single covalent bonds allows molecules to change shape - The binding of one molecule to another can cause the molecule to change shape

Answer 58

molecules may change their shape

Question 59

- Molecule containing an atom with a single, unpaired electron in its outer shell - Highly reactive molecules; can "steal" an electron from other molecules - Can form by exposure to radiation and some toxins - Examples: O, OH, NO2 - Can cause cell damage - Can kill invading bacteria - Benefits of ANTIOXIDANTS

Answer 59

free radicals

Question 60

protective compounds that can donate electrons without becoming highly reactive themselves

Answer 60

benefits of antioxidants

Question 61

- When one or more substances are CHANGED into other substances - Reactants > Products

Answer 61

chemical reactions

Question 62

- Require a source of energy - In living organisms, they often require an enzyme as ENZYME speeds reaction rate - Tend to proceed ina particular direction but will eventually reach equilibrium - Occur in LIQUID (water)

Answer 62

properties of chemical reactions

Question 63

- Bodies of all organisms are largely composed of water - Up to 95% of weight of certain plants comes from water - 60 to 70% of human body weight comed from water - Water is an important liquid in the surrounding environments of many organisms - Most chemical reactions in nature involve molecules that are dissolved in water, including reactions inside cells

Answer 63

properties of water