Atomic theory

Question 1

4 MAJOR POINTS OF ATOMIC THEORY:

Answer 1

1) Atoms are the smallest unit of matter
2) Atoms are unique to each element
3) Atoms have a positively charged center (nucleus)
surrounded by a negatively charged electron cloud
4) Splitting ng the atoms releases great amounts of energy

Question 2

subatomic particle

Answer 2

Any particles smaller than an atom

Question 3

3 types of subatomic particles:

Answer 3

1) Electrons: negatively charged
2) Protons: positively charged
3) Neutrons: neutral

Question 4

describe Electrons

Answer 4

• Have a charge of ‐1
• Are very light compared to protons and neutrons
• Are found in the shells orbiting the nucleus

Question 5

describe Protons

Answer 5

• Have a charge of +1
• Have an atomic mass of 1 AMU (atomic mass unit)
• Are found in the nucleus

Question 6

describe Neutrons

Answer 6

• Have NO CHARGE ‐ they are neutral
• Have a mass of 1 AMU
• Are found in the nucleus

Question 7

describe Atomic Number

Answer 7

• number of protons in the nucleus of an atom
• The atomic number is different for every element
• It gives each element its identity

Question 8

describe Ions

Answer 8

• Any charged atom is called an ion
• Atoms are only able to lose electrons in order to
become charged
• If an atom were to lose a proton it would simply
become a different element
• An atom will not become positively charged if it
gains an electron

Question 9

Cation

Answer 9

Positively charged ion

‐ An atom will lose electrons to become positive

Question 10

Anion

Answer 10

Negatively charged ion

‐ An atom will gain electrons to become negative

Question 11

describe Isotopes

Answer 11

Atoms of the same element that have
different mass numbers
• Different mass numbers are due to different
amounts of neutrons
• You can change the # of electrons or # neutrons
without changing the element
• Elements occur naturally as mixtures of isotopes