Chapter 2- Atomic Structure

Question 1

Electrons
Neutrons
Protons

Answer 1

Particle Relative charge Mass

Electron negative (-1) 1/1836

Proton Positive (+1) 1

Neuton Neutral (0) 1

Mass # = proton + neutron 23
Na
Atomic number = protons/electrons 11

Question 2

Electron Structure

Answer 2

• Electrons found in different shells around the nucleus if an atom
• Shells = Different energy levels
• First shell/lowest energy level = closest to Nucleus

First 20 atoms = 2.8.8.2 pattern
First shell has max of 2 always
All other full shells have 8
Outer shell can have any number from 1-8

Question 3

Electron Structure in Periodic Table

Answer 3

Number of electrons on outer shell = group number (column)
Number of shells = row

8 Groups = Electrons on outer shell
Group 1 = most reactive
Group 8 = least reactive - have full outer shell

Question 4

Isotopes

Answer 4

Iso = Same
Atoms of same element
Different # of neutrons
Same protons 
E.g carbon¹² = 6 protons 6 neutrons
      Carbon¹³ = 6 protons 7 neutrons
Abundance = How many there are

Working out isotopes - 75% 35Cl, 25% 37 Cl
(75x 35) + (25x37)
——————- = 35.5
100