2/3- Ch. 2 (Exam 1)

Question 1

What is an element?

Answer 1

Cannot be changed by chemical reactions into other forms of matter

Cannot be broken down by ordinary chemical reactions

Question 2

What is matter?

Answer 2

Anything that takes up space and has mass

Question 3

What are the elements present in an organism?

Answer 3

N- nitrogen
C- carbon
O- oxygen
H- hydrogen

Question 4

What is an atom?

Answer 4

Smallest component of an element

Question 5

Where is the subatomic particle protons located and what is there charge?

Answer 5

Nucleus

Positive

Question 6

Where is the subatomic particle neutron located and what is there charge?

Answer 6

Nucleus

No charge

Question 7

Where is the subatomic particle electron located and what is there charge?

Answer 7

Electron shell or energy level

Negative

Question 8

What is the mass of a proton, electron and neutron?

Answer 8

Proton- 1 amu
Neutron- 1 amu
Electron- 0 amu

Question 9

What is the units mass is measured?

Answer 9

Amu

Atomic mass unit

Question 10

In the first energy level of an electron shell, what is the maximum number of electrons?

Answer 10

2

Question 11

In the second energy level of an electron shell, what is the maximum number of electrons?

Answer 11

8

Question 12

What is the valence shell?

Answer 12

Outermost energy level

Electrons present in this shell determines the chemical characteristics of the element

Question 13

What is potential energy?

Answer 13

“Stored” energy

Valence electrons have greatest amount of potential energy in the atom

Question 14

What is the atomic #?

Answer 14

of protons (IDs the element)

Top number

Question 15

What is the mass #?

Answer 15

of protons plus # of neutrons

Bottom number

Question 16

What is a noble gas?

Answer 16

When valence shells are filled to max then the atom of element is unreactive (not going to participate in chemical reactions)

Inert (not going to react)

Ex: Helium (He)

Question 17

What does the atomic number do?

Answer 17

Determines which element it is

Question 18

What does the neutrons do?

Answer 18

Determine isotope

Question 19

What do the valence electrons do?

Answer 19

Determines chemical behavior

Question 20

What is an isotope?

Answer 20

Atom of element with different # of neutrons

Mass # is different

Question 21

What is a half life?

Answer 21

Many isotopes decay (release energy) in predictable ways

Ex: Tritium

Question 22

What is radioactivity?

Answer 22

Trace energy that is being released

Question 23

What are ions?

Answer 23

Charged atoms

Question 24

What is a neutral atom?

Answer 24

of protons are equal to # of electrons

Question 25

What are 2 types of ions and explain

Answer 25

1) cation- positive charge - more protons than electrons 2) anion- negative charge - less protons than electrons

Question 26

What are the 2 types of chemical bonds?

Answer 26

1) ionic bond | 2) covalent bonds

Question 27

What is an ionic bond?

Answer 27

Formation of ions Attraction between cation and anion Takes electrons

Question 28

What are covalent bonds and what are the 2 types?

Answer 28

Sharing of electrons pairs between atoms Overlap of the energy levels/ electron shells 1) non polar 2) polar

Question 29

What are non polar covalent bonds?

Answer 29

Equal attraction for electrons between 2 atoms in a covalent bond

Question 30

What are polar covalent bonds?

Answer 30

Unequal Sharing

Question 31

What are ionic compounds?

Answer 31

Can dissociate (separate)

Question 32

What is electronegativity?

Answer 32

Attraction of atom for electron Big difference in electronegativity it is an ionic bond Small difference it is a non polar covalent bond Medium difference it is a polar covalent bond

Question 33

What are hydrogen bonds?

Answer 33

Intermolecular bond (b/n molecules) Attraction between hydrogen and the negative end of a polar molecule One hydrogen bond is weak Many is stronger Hold structure of DNA

Question 34

What are trace elements?

Answer 34

Don’t exist in biological world in big amounts