Prep for General Chemistry Ch.3

How many protons does an atom with atomic number 17 have

17

How many electrons does a neutral atom with atomic number 17 have

17

How many neutrons does Cl-37 have

20

How many neutrons does P-31 have

16

How many neutrons does Zn-65 have

35

How many neutrons does C-14 have

8

How many neutrons does O-16 have

8

How many neutrons does N-15 have

8

Mass number formula

Protons + Neutrons

Neutron formula

Mass Number - Atomic Number

Proton formula

Atomic Number

Electron formula for neutral atoms

Equal to protons

Atomic number of phosphorus

15

Mass number of phosphorus-31

31

Neutrons in phosphorus-31

16

Atomic number of oxygen

8

Mass number of oxygen-16

16

Neutrons in oxygen-16

8

Atomic number of silver

47

47 protons identifies which element

Silver

17 protons identifies which element

Chlorine

35 protons identifies which element

Bromine

56 protons identifies which element

Barium

30 protons identifies which element

Zinc

14 protons identifies which element

Silicon

6 protons identifies which element

Carbon

8 protons identifies which element

Oxygen

7 protons identifies which element

Nitrogen

15 protons identifies which element

Phosphorus

Number of protons determines

Element identity

Number of neutrons determines

Isotope

Number of electrons determines

Charge

Atoms of same element can have different

Numbers of neutrons

Atoms of same isotope must have same

Protons and neutrons

Carbon-12 and Carbon-14 are

Isotopes

Hydrogen, deuterium, and tritium are

Isotopes

What stays constant among isotopes

Number of protons

What changes among isotopes

Number of neutrons

Nuclear symbol for carbon-12

¹²₆C

Nuclear symbol for carbon-14

¹⁴₆C

Nuclear symbol for phosphorus-31

³¹₁₅P

Nuclear symbol for oxygen-16

¹⁶₈O

Nuclear symbol for zinc-65

⁶⁵₃₀Zn

9 protons, 10 neutrons, 9 electrons

Fluorine-19

17 protons, 20 neutrons, 17 electrons

Chlorine-37

47 protons, 60 neutrons, 47 electrons

Silver-107

Atomic mass unit

amu

Abbreviation for atomic mass unit

amu

Atomic mass is also called

Average atomic mass

Atomic mass on periodic table is

Weighted average

Weighted average considers

Isotope masses and abundances

Percent abundance must be converted to

Decimal form

75% as a decimal

0.75

24.23% as a decimal

0.2423

Formula for weighted atomic mass

Σ(fraction × isotope mass)

Chlorine isotope masses

34.97 amu and 36.97 amu

Natural abundance of Cl-35

75.77%

Natural abundance of Cl-37

24.23%

Average atomic mass of chlorine

About 35.45 amu

If atomic mass is closer to smaller isotope

Smaller isotope is more abundant

If atomic mass is exactly halfway between two isotopes

Equal abundance

Most abundant chlorine isotope

Cl-35

Why average atomic mass is not a whole number

Weighted average of isotopes

Atomic mass of calcium

Found on periodic table

Atomic mass of aluminum

Found on periodic table

Atomic mass of lead

Found on periodic table

Atomic mass of barium

Found on periodic table

Atomic mass of iron

Found on periodic table

Group number helps predict

Number of valence electrons

Period number indicates

Highest occupied energy level

Elements in same group have similar

Chemical behavior

Elements in same period have same

Number of occupied energy levels

Alkali metals are found in

Group 1

Alkaline earth metals are found in

Group 2

Halogens are found in

Group 17

Noble gases are found in

Group 18

Most reactive nonmetals belong to

Halogens

Least reactive elements belong to

Noble gases

Noble gases are generally

Chemically inert

Bromine belongs to group

17

Magnesium belongs to group

2

Nitrogen belongs to group

15

Silicon is classified as

Metalloid

Carbon is classified as

Nonmetal

Iron is classified as

Metal

Sodium is classified as

Metal

Chlorine is classified as

Nonmetal

Metals are good conductors of

Heat and electricity

Nonmetals are poor conductors of

Heat and electricity

Metalloids are commonly used in

Electronics

Metalloids have properties

Intermediate between metals and nonmetals

Metals are generally

Shiny and ductile

Nonmetals are generally

Brittle and dull

Ductile means

Can be drawn into wires

Malleable means

Can be hammered into sheets

Location of metalloids

Along zigzag line

Location of metals

Left of zigzag line

Location of nonmetals

Right of zigzag line

Scientist associated with cathode ray experiment

Thomson

Scientist associated with gold foil experiment

Rutherford