Periodic Table of Elements

 

1. Elements are arranged horizontally in the Periodic Table in order of increasing proton number
2. Vertical column of element in the periodic table are called group and the group number is determined by the number if valence electrons in the atoms of the elements
3. Horizontal rows of the element in the Periodic Table are called periods and the periods number is determine by the number of electron-filled shell in atoms of the elements.
4. Element within a group have similar chemical properties because of their similar electronic structure

 

 

Group 18 Elements: The Noble or Inert Gases

 

1. Group 18 element are noble gases and are a collection of monoatomic and inert gases, with full outermost shells

 

 

Group 1 Elements: The Alkali Metals

 

1. Group 1 elements are alkali metals, a collection of very reactive metals which form positive ion with a charge of +1.
2. When moving down the group,
1. The boiling and melting points of the element decrease
2. The metal become softer
3. The reactivity of the alkali metals increase.

 

 

Group 17 Elements: The Halogens

 

1. Group 17 elements are halogens, a collection of very reactive non-metal which forms negative ions with a charge of -1.
2. When moving down the group
1. The boiling and melting point of the elements increase
2. The element change from gas to liquid followed by solid at room temperature
3. The reactivity of the element decrease.

 

 

Period 3: Elements

 

1. As we move across a period, the element shows changes, such as
1. Proton number and electron arrangement
2. Atomic radius
3. Melting point, boiling point and physical appearance
4. Metallic and non-metallic properties
5. The properties of oxides.
2. Silicon and germanium are the metalloids that used in the semiconductor industry which make chips for computer and other electronic product.

 

Transition Elements

 

1. The characteristic properties of transition metals
1. Their compound and aqueous solution of their ions are always coloured
2. They exhibit variable oxidation state
3. The element and their compound are good catalyst and commonly used in industry

 

 

EXERCISE

 

1. Explain the following

a)     When a piece of sodium metal is dropped into copper (II) sulphate solution, no copper metal is displaced. However , a blue precipitate is formed

b)     When we go down group 1 of the periodic table, reactivity increase

c)     Group 18 element exist as mono atoms

d)     As we go down group 17 of the periodic table, the melting point increases

2.  

a)     With example , give four characteristic of transition element

b)     A new element is discovered and give the name Pentin(Pn)

Pentin is placed below astatine

                                                              i.      Give 2 physical properties of pentin

                                                             ii.      With equation for each reaction, predict the three chemical properties of pentin.

3.  

a)     Write the formula of the oxides of elements in Period 3

Pick a basic oxide, an amphoteric oxide and an acidic oxide.

b)     The reactivity of group 17 element increases up the groups. Explain

c)     Cesium (Cs) is a metal in Group 1 of the Periodic Table. Predict two chemical properties of cesium.

 

 

4. “The reactivity of group 1 element increase from Li, Na, K”

You are required to carry out experiment to prove the above statement

Your answer should include the following

a)     Problem statement

b)     Hypothesis

c)     State all variable involved

d)     List of apparatus and chemicals

e)     Procedure

f)       Tabulation of result