2. The Periodic Table
• The periodic table is a tabular arrangement of the chemical elements,
ordered by their atomic number, and recurring chemical properties.
• A group or family is a column of elements in the periodic table. There
are a total of 18 numbered groups in the periodic table
• A period or series is a row of elements in the periodic table. In the
periodic table, there are a total of seven rows.
3.
4. The Periodic Table has 18 groups. Groups 1 – 2 (Group 1 A and 2 A) and 13 –
18 (Group 3A to 8A) are known as the Representative elements.
• Group 1A is known as the Alkali Metals
• Group 2A is known as the Alkaline Earth Metals
• Group 3A is known as the Boron Group
• Group 4A is known as the Carbon Group
• Group 5A is known as the Nitrogen Group
• Group 6A is known as the Chalcogens Group or Oxygen Group
• Group 7A is known as the Halogens
• Group 8A is known as the Noble Gases (all groups except the Noble gases
interact with other elements to be stable. Noble Gases have 8 complete
electrons, they are already stable, they don’t need to interact with other
elements).
• Groups 3 to 12 (Groups 1B to 8B) are known as the transition metals
5. Properties of Alkali Metals
The Alkali Metals have the following properties in common:
• They have low melting and boiling points compared to most other
metals
• They are very soft and can be cut easily with a knife They have low
densities.
• Lithium, sodium and potassium will float in water
• They react quickly with water, producing hydroxides and hydrogen gas
6. Properties of Alkali Earth Metals
The Alkaline Earth Metals have the following properties in common:
• They are shiny
• They are silvery - white
• They are somewhat reactive at standard temperature and pressure
• They have low densities
• They have low melting points
• They have low boiling points
7. Properties of Transition Metals
The Transition Metals have the following properties in common:
• They are very hard, usually shiny, ductile and malleable
• They have high melting points
• The have high boiling points
• They have high thermal conductivity
• They have high electrical conductivity
• They have high densities
8. Properties of Halogens
The halogens have the following properties in common:
• They are poor electrical conductors
• They are poor thermal conductors
• They form brittle solids
• They have low melting points
• The have low boiling points
9. • Valence electrons are electrons found on the outermost energy level.
The outermost energy level or shell is known as the valence shell.
For Representative elements (Groups 1A to 8A):
the number of valence electrons is equal to its group number.
For example:
Oxygen is found on Group 6A. Therefore, oxygen has six valence
electrons.
Neon is found on Group 8A, a noble gas. Therefore, neon has
eight valence electrons.
10. For Transition Metals:
Group 1B – 1 or 2 valence electrons
Group 2B – 2 valence electrons
Group 3B – 3 valence electrons
Group 4B – 2 to 4 valence electrons
Group 5B – 2 to 5 valence electrons
Group 6B – 2 to 6 valence electrons
Group 7B – 2 to 7 valence electrons
Group 8B – 2 or 3 valence electrons
11. TRENDS IN ATOMIC PROPERTIES IN THE
PERIODIC TABLE
Atomic Radius
Ionization Energy
Electron Affinity
Electronegativity
12. Atomic Radius
– size of the atom
In the Periodic Table of Elements as you move:
Downward – atomic radius increases
Right – atomic radius decreases
13.
14. Ionization Energy
– is the amount of energy needed to remove an
electron from an atom
- lowest on Francium, because its valence electron is
farthest from all of the nucleus
- highest on Helium
In the Periodic Table of Elements as you move:
Left to Right – ionization energy increases
15. Electron Affinity
– is the amount of energy needed to gain electron from
an atom
- Flourine has the highest Electron Afinity
- Noble gases is not affected
In the Periodic Table of Elements as you move:
Left to Right – electron afinity increases
16. Electronegativity
– is the ability of an atom to hold electrons tightly
- Flourine is the highest effective nuclear charge
- Noble gases is not affected
In the Periodic Table of Elements as you move:
Left to Right – electronegativity increases
