Biochemistry Chapter 2-AP Bio Part 2

Question 0

What are periods, and what do they correspond to?

Answer 0

The rows of the periodic table, corresponds to the number of electron shells in their atoms.

Question 1

What is the chemical behavior of an atom determined by

Answer 1

The distribution of electrons in the atom’s electron shells.

Question 2

What does the left to right sequence of elements corresponds to _______________

Answer 2

The sequential addition of electrons and protons

Question 3

All matter prefers to exist on what state of energy

Answer 3

Lowest available state of potential energy-first shell.

Question 4

What does the chemical behavior of atoms depend on

Answer 4

The number of electrons in its outermost shell.

Question 5

Valence electrons

Answer 5

Electrons in the outermost shell

Question 6

Valence shell

Answer 6

The outermost shell of electrons.

Question 7

An atom with a complete outside shell is

Answer 7

Unreactive

Question 8

Inert

Answer 8

Chemically unreactive (noble gases)

Question 9

Each concentric circles in an atom diagram represents

Answer 9

The average distance between an electron in that shell and the nucleus

Question 10

Orbital

Answer 10

The 3D space where an electron is found 90% of the time

Question 11

Describe the orbital(s) of the first electron shell

Answer 11

Only one spherical orbital ( called 1s)

Question 12

Describe the orbital(s) of the second shell

Answer 12

There are 4. One large spherical s orbital (2s). And 3 dumbbell shaped p orbitals (called 2p orbitals).

Question 13

Describe the orbital(s) for the 3rd shell and higher

Answer 13

Have s and p orbitals as well, and orbitals of more complex shapes.

Question 14

How many electrons can occupy an orbital

Answer 14

No more than 2

Question 15

The reactivity of an atom arises from what

Answer 15

The presence of unpaired electrons in one or more orbitals of its valence shell.

Question 16

Which electrons are involved in the atoms interacting with valence shells

Answer 16

Unpaired electrons

Question 17

Chemical bonds

Answer 17

Atoms held close together due to sharing or transferring valence electrons

Question 18

Covalent bond

Answer 18

The SHARING of a pair of valence electrons by 2 atoms.

Question 19

How do atoms have the ability to share electrons

Answer 19

The hydrogen atoms come close enough for their 1s orbitals to overlap.

Question 20

Molecule

Answer 20

2 or more atoms held together by covalent bonds

Question 21

Molecular formula

Answer 21

H2, incites the molecule consists of 2 hydrogen atoms

Question 22

Lewis dot structure

Answer 22

Element symbols are surrounded by dots that represent the valence electrons. (H:H)

Question 23

Structural formula

Answer 23

H—H, the line represents a single bond

Question 24

Single bond

Answer 24

A pair of shared electrons

Question 25

Double bond

Answer 25

Sharing of 2 pairs of valence electrons (o=o).

Question 26

Each atom that can share valence electrons has

Answer 26

a bonding capacity corresponding to the number of covalent bonds the atom can form.

Question 27

Valence

Answer 27

The bonding capacity of an atom, usually equals the number of unpaired electrons required to complete the atoms valence shell.

Question 28

What's the main component of natural gas

Answer 28

Methane

Question 29

Electronegativity

Answer 29

The attraction of a particular atom for the electrons of a covalent bond.

Question 30

The more electronegative an atom is ______________

Answer 30

The more strongly it pulls shared electrons toward itself.

Question 31

In a caovalent bond between 2 atoms of the same element

Answer 31

The electrons are shared equally because the 2 atoms have the same electronegativity.

Question 32

No polar covalent bond

Answer 32

Electrons in a covalent bond are shared equally because they have the same electronegativity. (Same element)

Question 33

Polar covalent bond

Answer 33

When an atom is bonded to a move electronegative atom, the electrons of the bond are not shared equally. These bonds vary on polarity, depending on the relative electronegativity of the 2 atoms.

Question 34

What is one of the most electronegative elements

Answer 34

Oxygen, it attracts shared electrons more strongly than hydrogen.

Question 35

What happens when 2 atoms are so unequal in their attraction for valence electrons

Answer 35

The more electronegative atom completely strips away an electron from its partner.

Question 36

Ions

Answer 36

The 2 oppositely charged atoms after one atoms strips an electron from the other.

Question 37

Cation

Answer 37

A positively charged ion

Question 38

Anion

Answer 38

A negatively charged ion

Question 39

Ionic bond

Answer 39

The attraction of 2 atoms of opposite charge, which doesn't have to be due to the transfer of electrons from that one atom to the other.

Question 40

Ionic compounds (salts)

Answer 40

Compounds formed by ionic bonds

Question 41

Salt crystals

Answer 41

An aggregate of vast numbers of cations and anions bonded by their electrical attraction and arranged in a 3D lattice.

Question 42

What does ion also apply to

Answer 42

Entire molecules that are electrically charged

Question 43

What other factor affects ionic bonds

Answer 43

Environment

Question 44

Why are ionic bonds weaker in water

Answer 44

Each ion is partially shielded by its interactions with water molecules

Question 45

Hydrogen bond

Answer 45

The attraction between a hydrogen and an electronegative atom (usually oxygen or nitrogen).

Question 46

How are hydrogen bonds possible

Answer 46

When a hydrogen atom is covalently bonded to an electronegative atom, the hydrogen atom has a partial positive charge that allows it to be attracted to different electronegative atom nearby.

Question 47

Positively and negatively charged atoms are additionally possible with what bonds

Answer 47

Nonpolar covalent (electrons aren't always evenly distributed)

Question 48

Van der Waals interactions

Answer 48

The not always evenly distributed electrons in non polar covalent bonds that create ever changing regions of positive and negative charge, this allows all atoms and molecules to stick to one another. Individually weak, occur only when atoms and molecules are close together.

Question 49

How can these interactions be powerful

Answer 49

When many occur simultaneously

Question 50

Van der Waals interactions, hydrogen bonds, ionic bonds in water and other weak bonds may forms ______

Answer 50

not only between molecules but also between parts of large molecules such as protein.

Question 51

A molecule consisting of 2 atoms is always what

Answer 51

Linear

Question 52

Shapes are determined by what

Answer 52

The positions of the atoms' orbitals

Question 53

When an atom forms covalent bonds, what happens to the orbitals in the valence shells

Answer 53

They undergo rearrangement

Question 54

How do atoms with valence electrons in s and p orbitals change

Answer 54

The single s and 3 p orbitals form 4 new hybrid orbitals shaped liked identical teardrops extending from the region of the atomic nucleus The the larger ends of the teardrops and connected with lines, a tetrahedron is formed.

Question 55

In water molecules 2 of the hybrid orbitals are shared with what

Answer 55

Hydrogens, resulting in a v shaped molecule.

Question 56

How does the methane molecule have the shape of a completed tetrahedron

Answer 56

All four hybrid orbitals of the carbon atom are shared with hydrogen atoms. The carbon nucleus is at the center, with its 4 covalent bonds radiating to hydrogen nuclei at the corners of the tetrahedron.

Question 57

What does molecular shape determine

Answer 57

How biological molecules recognize and respond to one another with specificity.

Question 58

Chemical reactions

Answer 58

The making and changing of chemical bonds leading to changes in the composition of matter.

Question 59

Reactants

Answer 59

The starting materials

Question 60

Products

Answer 60

What is produced

Question 61

What do coefficients indicate

Answer 61

The number of molecules involved. (2NH)

Question 62

Matter is _______ in a chemical reaction

Answer 62

Conserved. Reactions cannot create or destroy atoms but can only rearrange the electrons among them.

Question 63

Photosynthesis

Answer 63

6 H2O + 6 CO2 -----> C6H12O6 + 6 O2

Question 64

All chemical reactions are

Answer 64

Reversible

Question 65

Opposite 2 headed arrows indicate

Answer 65

The reaction is reversible

Question 66

The greater the concentration of reactant molecules

Answer 66

The more frequently they collude with one another and have an opportunity to react and form products.

Question 67

As products accumulate

Answer 67

Collisions resulting in the reverse reaction become more frequent

Question 68

What happens when eventually the forward and reverse reactions occur at the same rate

Answer 68

The relative concentrations of products and reactants stop changing.

Question 69

Chemical equilibrium

Answer 69

The point at which the reactions offset one another exactly. Reactions are still going on, but with no net effect on the concentrations of reactants and products.

Question 70

What does equilibrium NOT mean

Answer 70

The reactants and products are equal in concentration, it only means their concentrations have stabled at a specific ratio.