Chem History/Isotope Symbols

Question 1

Why is mass # always a whole #?

Answer 1

Mass # = sum of # protons and neutrons
Partial proton or neutron DNE

Question 2

Atomic # of an atom = ?

Answer 2

of protons

Question 3

how do protons, electrons and neutrons compare in the atoms of various isotopes of an element?

Answer 3

Same # of protons and electrons
Diff # of neutrons

Question 4

Isotopic notation: A represents ?

Answer 4

Mass #

Question 5

Isotopic notation: Z represents ?

Answer 5

Atomic #

Question 6

In various isotopes of an element, what remains the same, mass number (A) or atomic number (Z)?

Answer 6

Atomic number (Z)

Question 7

Dalton’s discovery?

Answer 7

Found that each element is composed of atoms which are unique and can combine in ratios of small whole #’s

Question 8

Thompson’s discovery

Answer 8

Discovered electron and found the electron charge-to-mass ratio

Question 9

Rutherford’s discovery

Answer 9

Devised model of nuclear atom w positive charge and most of mass in nucleus

Question 10

Milkan’s Discovery

Answer 10

-Found electron has neg. charge
-Used Thompson’s charge-to-mass ratio to find mass of electron

Question 11

In Isotope Symbols,
Atomic # (Z) =

Answer 11

of protons

Question 12

In Isotope Symbols,
Atomic mass (A)=

Answer 12

Protons + neutrons

Question 13

In Isotope Symbols,
Charge of ele. =

Answer 13

Protons - electrons