Lecture 2: Chemistry Comes To Life

Question 1

Matter is

Answer 1

Anything that takes up space and has mass

Question 2

Matter is made up of

Answer 2

Elements

Question 3

Elements are

Answer 3

Substances that cannot be broken down to other substances by chemical reactions

Question 4

A compound is

Answer 4

A substance consisting of 2 or more different elements in a fixed ratio

Question 5

Compounds have

Answer 5

Characteristics (emergent properties) different from those of its elements

Question 6

Atoms are

Answer 6

The smallest unit of matter that still retains the properties of an element (neutral)

Question 7

Atoms are composed of

Answer 7

Subatomic particles- neutrons, protons, electrons

Question 8

Charge of Neutrons

Answer 8

Neutral

Question 9

Charge of protons

Answer 9

Positive

Question 10

Charge of electrons

Answer 10

Negative

Question 11

What forms the atomic nucleus?

Answer 11

Protons and neutrons

Question 12

Electrons form

Answer 12

A “cloud” around nucleus

Question 13

An element’s atomic number is

Answer 13

The number of protons in its nucleus

Question 14

An element’s mass number equals

Answer 14

The sum of protons and neutrons in the nucleus

Question 15

Atomic mass is

Answer 15

An atom’s total mass, can be approximated by mass number

Question 16

All atoms of an element have the same number of _______, but may differ in number of _______.

Answer 16

Protons; neutrons

Question 17

Radioactive isotopes

Answer 17

Decay spontaneously, giving off particles and energy

Question 18

Unstable isotopes emit

Answer 18

Radiation to regain a stable state

Question 19

Radioactive tracers are

Answer 19

Used to track atoms through metabolism

Question 20

Valence electrons are

Answer 20

Electrons in the outermost shell

Question 21

Valence shell

Answer 21

Outermost shell

Question 22

Chemical behavior of an atom is mostly determined by

Answer 22

Number of valence electrons

Question 23

Elements in a full valence shell are

Answer 23

Chemically inert

Question 24

Chemically inert

Answer 24

Not reactive

Question 25

Orbital

Answer 25

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

Question 26

How many electrons can a single orbital contain?

Answer 26

2

Question 27

In an orbital, atoms

Answer 27

Interact in a way that completes their valence shells

Question 28

Atoms with incomplete valence shells can

Answer 28

Share or transfer electrons with certain other atoms

Question 29

Chemical bonds are

Answer 29

Attractions that hold atoms together when they share or transfer valence electrons.

Question 30

Covalent bond

Answer 30

Sharing of a pair of valence electrons by 2 atoms

Question 31

What is the strongest chemical bond?

Answer 31

Covalent bond

Question 32

In a covalent bond, shared electrons

Answer 32

Count as part of each atom’s valence shell

Question 33

Single covalent bond is

Answer 33

A sharing of one pair of valence electrons

Question 34

Double covalent bond is

Answer 34

A sharing of two pairs of valence electrons

Question 35

Electronegativity is

Answer 35

Atom’s attraction for electrons in a covalent bond

Question 36

The more electronegative an atom is,

Answer 36

The more strongly it pulls shared electrons toward itself

Question 37

In a nonpolar covalent bonds

Answer 37

Atoms share electrons equally

Question 38

Polar covalent bonds are when

Answer 38

One atom is more electronegative, and atoms do not share electrons equally

Question 39

In a polar covalent bond unequal sharing of electrons

Answer 39

Causes a partial positive or negative charge for each atom or molecule

Question 40

In Ionic bonds

Answer 40

Atoms sometimes strip electrons from their bonding partners.

Question 41

Ions are

Answer 41

The two resulting oppositely charged atoms or molecules from an ionic bond

Question 42

Cation

Answer 42

Positively charged ion

Question 43

Anion

Answer 43

Negatively charged ion

Question 44

When do Hydrogen bonds form?

Answer 44

When a hydrogen atom covalently bonds to one electronegative atom and is also attracted to another electronegative atom

Question 45

Hydrogen atoms have

Answer 45

A partial positive charge that allows it to be attracted to a different electronegative atom with a partial negative charge nearby

Question 46

Van der Waals Interactions are

Answer 46

Attractions between molecules that are close together as a result of these charges

Question 47

Van der Waals interactions explaination

Answer 47

If electrons are not evenly distributed, they may accumulate by chance in one part of a molecule

Question 48

In chemical reactions, the greater the concentration of reactant molecules,

Answer 48

The more frequently they collide with one another and form products As products accumulate, collisions resulting in reverse reactions become more frequent

Question 49

Chemical equilibrium

Answer 49

Eventually, forward and reverse reactions occur at the same rate, and relative concentrations of products and reactants stop changing Concentrations aren’t equal