Chap 2 -1 Flashcards Preview

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Flashcards in Chap 2 -1 Deck (20):
1

What are elements?

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

2

What do columns denote in periodic charts?

similar properties/ behaviors

3

Most of an atom's volume is?

empty space

4

90% of the body is composed of?

C,H,O,N

5

Trace elements in the body is how much percent?

less than .01

6

What are atoms?

smallest particles that retain properties of an element

7

Describe protons

+
1amu
in nucleus
define the element

8

Describe neutrons

O
1 amu
in nucleus
define the isotope

9

Describe electrons

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

10

How are atoms electrically neutral?

when protons = electrons

11

What is the atomic number?

number of protons atom has
never changes
determines the element

12

What is the mass number?

number of protons and neutrons
can change (neutrons)

13

What are isotopes?

atoms w/ variable numbers of neutrons
unstable
nucleus unbalanced

14

What are radioactive isotopes?

they emit energy in form of particles - radioactive decay

15

What are electron shells?

represent distance of electrons from nucleus

16

What does vacancies in the outermost shell indicate?

that its reactive

17

1 electron shell can hold a max of?

2 electrons

18

Electrons move in?

pairs in orbitals

19

What happens when electrons interact?

Chemical bond
Mixture/solution

20

What is a chemical bond?\

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