chapter 2

Question 1

stm stands for

Answer 1

scanning tunneling microscopy

Question 2

what does an stm do

Answer 2

the movement of the tip is used to create an image wit atomic resolution . it uses a very fine point and projects voltage from the tip to create a 2 dimensional image

Question 3

another use for stm’s

Answer 3

to move atoms

Question 4

an ______ is the smallest identifiable unit of an element

Answer 4

atom

Question 5

how many natural elements

how many synthetic elements

Answer 5

91

20

Question 6

who created the atomic theory

Answer 6

John dalton

Question 7

each element is composed of tiny, indestructible particles called _____

Answer 7

atoms

Question 8

all _____ of a given element have the same mass and other properties that distinguish them from the atoms of other elements

Answer 8

atoms

Question 9

_____ combine in simple, whole number ratios (integers) to form compounds

Answer 9

atoms

Question 10

_____ of one element cannot change into atoms of another element. in a chemical reaction, atoms change the way they are bound together with other atoms to form a new substance.

Answer 10

atoms

Question 11

____ are the basic unit of a chemical element

Answer 11

atoms

Question 12

how is a protons, neutron, or electron’s charge measured

Answer 12

colombs

Question 13

proton’s charge :

Answer 13

1.60218 * 10 ^-19

Question 14

electron’s charge:

Answer 14

-1.60218 * 10^-19

Question 15

the discovery of _______ debunked the plum pudding model

Answer 15

radioactivity

Question 16

______ is the number of protons in the nucleus of a n atom

Answer 16

atomic number

Question 17

_____ is the number of protons plus the number of neutrons in an atom

Answer 17

mass number

Question 18

_____ are atoms of the same element that have different numbers of neutrons

Answer 18

isotopes

Question 19

species with a net charge. the number of protons and electrons in the species are not equal

Answer 19

ions

Question 20

negative; have more electrons than protons

Answer 20

anions

Question 21

positive; have more protons than electrons

Answer 21

cations

Question 22

ions can either be ______ (derived from a single atom) or _______ ( a group of atoms with an overall charge)

Answer 22

monatomic

polyatomic

Question 23

who developed the periodic law

Answer 23

Dmitri Mendeleev

Question 24

vertical columns

Answer 24

groups

Question 25

horizontal rows

Answer 25

periods

Question 26

in chemical reactions, metals tend to form ______ (lose electrons) and nonmetals tend to form ______ (gain electrons)

Answer 26

cations | anions

Question 27

list the metalloids

Answer 27

``` boron silicon germanium arsenic antimony tellurium polonium ```

Question 28

noble gases

Answer 28

``` helium neon argon krypton xenon radon ```

Question 29

halogens

Answer 29

fluorine chlorine bromine iodine

Question 30

alkali metals

Answer 30

``` hydrogen lithium sodium potassium rubidium cesium francium ```

Question 31

alkali earth metals

Answer 31

``` beryllium magnesium calcium strontium barium radium ```

Question 32

a _____ is a means of counting the large number of particles in samples

Answer 32

mole

Question 33

avogrado's number

Answer 33

6.022 *10^23 particles/ mole

Question 34

the mass of 1 mole of atoms of an element is its _____

Answer 34

molar mass