Metals and Non-Metals _ Part 1

Metals and Non-Metals

by utkersh bora

​What are Metals?

With the exception of hydrogen, all elements that form positive ions by losing electrons during chemical reactions are called metals. Metals have 1 to 3 electrons in their Valence Shell.

They are characterized by bright luster, hardness, ability to resonate sound and are excellent conductors of heat and electricity. Metals are solids under normal conditions except for Mercury.​

​Physical Properties of Metals

​State: Metals are solids at room temperature with the exception of mercury, (Gallium and Caesium are liquid on hot days).

Lustrous:

Malleable:

​Sonorous:

Hard: All metals are hard except sodium and potassium, which are soft and can be cut with a knife.

Valency: Metals typically have 1 to 3 electrons in the outermost shell.

Good conductors: Silver and copper are the two best conductors of heat and electricity. Lead is the poorest conductor of heat. Bismuth, mercury are also poor conductors

Density: Metals have high density and are very heavy. Iridium and osmium have the highest densities. Lithium, Potassium and Sodium have a low density so they even float on water.

Multiple Choice

A metal which is lighter than water is:

• Lithium

• Gold

• Silver

• Iron

Multiple Choice

Which of the following two metals will melt at body temperature (377⁰C)? Gallium, Magnesium, Caesium. Aluminium.

• Gallium, Caesium.

• Gallium, Aluminium.

• Magnesium, Caesium.

• Caesium. Aluminium.

Multiple Choice

Metals generally are:

Hint: Oxidising agent takes electrons, Reducing agent gives electrons.

• Reducing agents

• Oxidising agents

• both oxidising and reducing agents

• None of these

Multiple Choice

Which is the most abundant metal in the Earth's crust?

• Iron

• Aluminium

• Carbon

• Silicon

Multiple Choice

Which of the following statements regarding metals is true?

• All Metals are solid in Nature.

• Metals can be used to make handles of Cooking Utensils

• Generally most of the metals have high melting and boiling points.

• Gold is used to make electrical wires of our homes.

Multiple Choice

An element 'A' is very soft and can be cut with a knife. It is very reactive and is kept dipped in Kerosene Oil. It reacts vigorously with water. Which element is 'A'?

• Mg

• Na

• P

• Ca

Multiple Choice

The electronic configuration of three elements X,Y and Z are:

X - 2,8

Y - 2, 8, 7

Z-2, 8, 2

Which of the following statements is correct?

• X is a metal

• Y is a Metal

• Z is a non Metal

• Y is a Non-Metal and Z is a Metal

​Chemical Properties of Metals

​Reaction with Oxygen:

​Almost all metals combine with oxygen to form basic metal oxides.

Metal + Oxygen → Metal oxide

For example, when copper is heated in air, it combines with oxygen to form copper(II) oxide, a black oxide.

2Cu + O₂ → 2CuO

Similarly, aluminium forms aluminium oxide.

4Al + 3O₂ → 2Al₂O₃​

​react with oxygen even at high temperatures.

​Reactivity of metals on the basis of their reactions with O2.

​All metals do not react with oxygen at the same rate. Different metals show different reactivities towards oxygen.

1. ​Metals such as potassium and sodium react so vigorously that they catch fire if kept in the open.

2. ​At ordinary temperature, the surfaces of metals such as magnesium, aluminium, zinc, lead, etc., are covered with a thin layer of oxide.

3. ​Iron does not burn on heating but iron filings burn vigorously when sprinkled in the flame of the burner.

4. ​Copper does not burn, but the hot metal is coated with a black coloured layer of copper(II) oxide.

5. ​Silver and gold do not react with oxygen even at high temperatures.

​

​Amphoteric Oxides

Some metal oxides, such as aluminium oxide, zinc oxide show both acidic as well as basic behaviour. Such metal oxides which react with both acids as well as bases to produce salts and water are known as amphoteric oxides.

Aluminium oxide reacts in the following manner with acids and bases – Al₂O₃ + 6HCl → 2AlCl₃ + 3H₂O

Al₂O₃ + 2NaOH → 2NaAlO₂ (Sodium aluminate) + H₂O​

​Alkalis

Most metal oxides are insoluble in water but some of these dissolve in water to form alkalis. Sodium oxide and potassium oxide dissolve in water to produce alkalis as follows –

Na₂O(s) + H₂O(l) → 2NaOH(aq)

K₂O(s) + H₂O(l) → 2KOH(aq)​

Multiple Choice

Why are Sodium and Potassium kept immersed in kerosene oil ?

• Potassium and Sodium  are very reactive. They catch fire if kept in the open.

• To prevent the formation of the oxide layer.

• To prevent them from Corrosion.

• They react with CO₂ present in the Atmosphere and form Acids.

Multiple Choice

What protects the surfaces of metals such as magnesium, aluminium, zinc, lead, etc from further oxidation?

• Oxide Layer

• Carbonate Layer

• Zinc Coating

• Oil Coating

Multiple Choice

Which of the following statements is true?

• Both Iron piece and iron fillings burn vigorously when put in the flame of the burner.

• Iron piece burns on heating but iron fillings do not burn when sprinkled in the flame of the burner.

• Iron piece does not burn on heating but iron fillings burn vigorously when sprinkled in the flame of the burner.

• None of the above

Multiple Choice

Most Metals react with oxygen to form:

• neutral oxides

• basic oxides

• acidic oxides

• None of these

Multiple Choice

A Metal reacts with Oxygen to give a compound that is used in the white washing process, The Compound dissolves in water also releasing heat in the process. Identify the metal.

• Calcium

• Carbon

• Silicon

• Iron

Multiple Choice

Although metals form basic oxides, which metal among the following forms Amphoteric Oxides?

• Na

• Ca

• Al

• Cu

Multiple Choice

Whati is Anodising?

• It is the process of applying a protective zinc coating to steel or iron, to prevent rusting.

• It is the process that adds a surface layer of metal to another type of metal.

• It is the process of forming a thick oxide layer of aluminium on the surface of any object. This aluminium oxide coat makes the object resistant to further corrosion.

• None of the above

​What happens when Metals react with Water?

​Metals react with water and produce a metal oxide and hydrogen gas. Metal oxides that are soluble in water dissolve in it to further form metal hydroxide.

Metal + Water → Metal oxide + Hydrogen

Metal oxide + Water → Metal hydroxide

​2Na + 2H₂O → 2 NaOH + H₂

​Reactivity of Metals with Water

Metals like potassium and sodium react violently with cold water. In case of sodium and potassium, the reaction is so violent and exothermic that the evolved hydrogen can immediately catch fire.

2K(s) + 2H₂O(l) → 2KOH(aq) + H₂ (g) + heat energy

2Na(s) + 2H₂O(l) → 2NaOH(aq) + H₂ (g) + heat energy

The density of Sodium, Potassium and Lithium is less than that of water and so they float when put in water.

Multiple Choice

Potassium reacts with water vigorously releasing bubbles of gas X. When a burning matchstick is brought close to the mouth of the test tube, it burns out with a pop sound. Identify the gas:

• O₂

• H₂

• NH₃

• None of the above

• ​The reaction of calcium with water is relatively less violent. The heat evolved is not sufficient for the hydrogen to catch fire.                             Ca(s) + 2H₂O(l) → Ca(OH)₂ (aq) + H₂ (g)                                            Calcium starts floating because the bubbles of hydrogen gas formed stick to the surface of the metal.

• ​Magnesium does not react with cold water. It reacts with hot water to form magnesium hydroxide (Mg(OH)₂) and hydrogen. It also starts floating due to the bubbles of hydrogen gas sticking to its surface.

• ​Metals like aluminium, iron and zinc do not react either with cold or hot water. But they react with steam to form the metal oxide and hydrogen.   2Al(s) + 3H₂O(g) → Al₂O₃ (s) + 3H₂ (g)

• ​For a reaction to happend between a metal and water, the reactivity of the metal should be more than Hydrogen. Metals such as lead, copper, silver and gold do not react with water at all.

Multiple Choice

Why does Magnesium float when reacting with water?

• Due to its density

• Due to the bubbles of hydrogen gas sticking to its surface

• Due to its Hydrophobic Nature

• None of the above

Multiple Choice

Which of the following statements is true?

• Aluminium reacts with steam to form Aluminium oxide and hydrogen. 

• Aluminium reacts with cold water to form Aluminium Oxide and Hydrogen.

• Aluminium reacts with hot water to form Aluminium Oxide and Hydrogen.

• None of the above.

Multiple Choice

Which of the following metals does not react with water?

• Aluminium

• Sodium

• Lead

• Calcium

Multiple Choice

Mg dissolves in hot water to form:

• MgO

• Mg(OH)₂

• MgOH

• MgO.Mg(OH)₂

Multiple Choice

Zn + H₂O (Steam) → A + B

In the equation, A and B are:

• Zn, H only

• ZnH₂ and O₂

• ZnO₂ & O₂

• ZnO and H₂