Chap 2 -1

Question 1

What are elements?

Answer 1

Pure substances
Each consists of 1 atom type
94 occur naturally on Earth

Question 2

What do columns denote in periodic charts?

Answer 2

similar properties/ behaviors

Question 3

Most of an atom’s volume is?

Answer 3

empty space

Question 4

90% of the body is composed of?

Answer 4

C,H,O,N

Question 5

Trace elements in the body is how much percent?

Answer 5

less than .01

Question 6

What are atoms?

Answer 6

smallest particles that retain properties of an element

Question 7

Describe protons

Answer 7

+
1amu
in nucleus
define the element</p>

Question 8

Describe neutrons

Answer 8

O
1 amu
in nucleus
define the isotope

Question 9

Describe electrons

Answer 9

-
no weight
in cloud/orbiting
define behavior
decide whether atoms will interact/bond

Question 10

How are atoms electrically neutral?

Answer 10

when protons = electrons

Question 11

What is the atomic number?

Answer 11

number of protons atom has
never changes
determines the element

Question 12

What is the mass number?

Answer 12

number of protons and neutrons
can change (neutrons)

Question 13

What are isotopes?

Answer 13

atoms w/ variable numbers of neutrons
unstable
nucleus unbalanced

Question 14

What are radioactive isotopes?

Answer 14

they emit energy in form of particles - radioactive decay

Question 15

What are electron shells?

Answer 15

represent distance of electrons from nucleus

Question 16

What does vacancies in the outermost shell indicate?

Answer 16

that its reactive

Question 17

1 electron shell can hold a max of?

Answer 17

2 electrons

Question 18

Electrons move in?

Answer 18

pairs in orbitals

Question 19

What happens when electrons interact?

Answer 19

Chemical bond

Mixture/solution

Question 20

What is a chemical bond?\

Answer 20

attractive forces that fill electron vacancies and unite atoms into molecules/compounds