Atoms and Isotopes

Question 1

how do we describe atoms

Answer 1

they are defined by the number of subatomic particles that they have

Question 2

what are elements

Answer 2

substanes made from only one atom

Question 3

how are elements defined

Answer 3

by the number of protons that it has

Question 4

what letter do we use to represent Atomic number and atomic mass number

Answer 4

atomic number: Z
atomic mass number: A

Question 5

what are isotopes

Answer 5

atoms of one element that have the same number of protons but different numbers of neutrons.

they have same chemical properites (how they react)
they have differnet physical properties (mass and density)

Question 6

how do radioisotopes form

Answer 6

some isotopes have a significantly higher number of neutrons and therefore become radioactive

Question 7

what is relative atomic masss

Answer 7

the mass of an isotope compared to the mass of carbon-12 is called a relative atomic mass

Question 8

what is the standard chosen for relative atomic mass

Answer 8

carbon 12

Question 9

calculation for relative atomic mass

Answer 9

Ar = (% of relative isotopic mass + % of relative isotopic mass)/100