Atomic Structure & Isotopes

Question 1

John Dalton’s Billiard Ball Model

Answer 1

• First way to represents atom
• Matter is made up of small, indivisible particles called atoms
• Same/diff elements have the same /diff properties
• In chemical reactions, atoms rearrange, nothing new is created of desytyed (conversation of mass)
• Atoms of two or more elements combine in constant ratios to form new substances

Question 2

J.J. Thomson’s Plum Pudding Model

Answer 2

• Atoms have negatively charged electrons
• Electrons are distributed evenly in an atom
• Positive charges should balance out negative charges to make atom balanced
• States what’s inside a atom
• States everything’s spread out all over the place

Question 3

Rutherford’s Gold Foil Experiment

Answer 3

High speed particles = positive
Based on JJ model

Question 4

Gold Foil Predictions

Answer 4

Will have not major deflections due to particles being spaced out evenly

Question 5

Gold Foil Observations

Answer 5

Used gold foil and shot positively charged particles
The particles are hitting another light charge, being very concentrated, causing deflections

Question 6

Chadwick’s Neutrons

Answer 6

Nueluces had neutrons (neutral charged particles) and protons (positive charge particles)
Mass of protons= mass of nutrons

Question 7

Bohr’s Energy Levels

Answer 7

Electrons are in energy levels, holding a specific amount of electrons
Can not be used for bigger elements

Question 8

The Elements

Answer 8

The atom is the smallest part of an element that has properties of element

Question 9

Electrons and Protons

Answer 9

of electrons = # of protons in neutral atom

number of electrons = # of protons in neutral atom

Question 10

Neutrons and Mass

Answer 10

of neutrons Depends on number of mass in nucleus

number of neutrons depends on number of mass in nucleus
Mass number= number of protons + number of neutrons

Question 11

Isotopes

Answer 11

Different version of an element, with changes of neutrons or mass

Question 12

Average Atomic mass

Answer 12

• Average of atomic masses of isotopes
• Found on periodic table
• Tells us which isotope is most amount (which number is closer to isotope)
• Decimal value tells us that there are isotopes (must have been added and divided)
• Uses the unit amu (μ)

Question 13

Determining Isotopic Abundance

Answer 13

• Uses Mass spectrometer
• Figure out percentages/ isotopic abundance
• Turns substances into gas through heating
• Electron beam source enters and interacts with sample
• Vapour is not a charge particle, so it makes gas charged ion
• Ions are accelerators and detectors at end
• Uses computers to determine isotopic abundance

Question 14

Unstable isotopes

Answer 14

• Some isotopes are unstable and release nuclear radiation
• Nuclear radiation can be energy or small particles

Question 15

Radioactive decay

Answer 15

When unstable isotopes disintegrate

Question 16

Nuclear radiation

Answer 16

3 types of nuclear radiation

Question 17

Alpha particles (α)

Answer 17

Positively charged particles
Have same structure as nucleus in helium atom
Equations use He instead of α
Travels fast
goes through paperonly

Question 18

Beta particles (β)

Answer 18

Negatively charged particles
Identical to electrons
goes through appe rbut not allimium

Question 19

Gamma rays (γ)

Answer 19

High form of electromagnetic energy radiation

Question 20

Radioisotopes

Answer 20

Isotopes that decay to emit nuclear radiation
Uranium

Question 21

Useful Radioisotopes

Answer 21

• Iodine 131
  Treats overactive thyroid gland
• Americium 241
  Used in smoke detectors
• Cobalt 60
  Food irradiation
• Carbon 14 and potassium 40
  Archeology dating

Question 22

Row

Answer 22

Known as period
Across/horizontal
Same # of energy levels

Question 23

Column

Answer 23

Known as group
Vertical/down
Same # of valence electrons

Question 24

electron

Answer 24

outside neucleus
-1 charge
mass close to 0

Question 25

proton

Answer 25

in neuclus
mass close to 1
+1 charge

Question 26

neutron

Answer 26

in neuclus
charge of 0
mass of 1

Question 27

What makes the atoms of one element different from the atoms of another element?

Answer 27

number of protons in neuclues