Tag: physical properties of metals and non-metals

Questions Related to physical properties of metals and non-metals

Metals have:

  1. high melting and boiling point

  2. low melting and boiling point

  3. high melting and low boiling point

  4. low melting and high boiling point


Correct Option: A
Explanation:

1) High melting and boiling point

2) Metallic bonding is the strong attraction between closely packed positive metal ions and a 'sea' of delocalised electrons.

3) The attraction between the metal ions and the delocalised electrons must be overcome to melt or to boil a metal.

4) These attractive forces are strong, so metals have high melting and boiling points.

Sodium and potassium  are soft even after being metals because of:

  1. strong intermolecular forces

  2. weak cohesive forces

  3. high melting point

  4. low boiling point


Correct Option: B
Explanation:

Hardness of a metal is determined by the strong cohesive forces between the atoms. The cohesive forces between atoms of these metals are very weak. The bonding in these metals is weak and electrons are not located over a single atom but over a number of atoms. The weak bonding results in softness of metal.

A metal which is lighter than water is:

  1. lithium

  2. gold

  3. silver

  4. iron


Correct Option: A
Explanation:
Lithium has a density of (0.534 g/cm3) which is lower than water (1 g/cm$^3$). Two other metallic elements are less dense than water. Potassium has a density of 0.862 g/cm$^3$ while sodium has a density of 0.971 g/cm$^3$. All of the other metals on the periodic table are denser than water. While lithium, potassium, and sodium are all light enough to float on water, they are also highly reactive.

Metals generally extracted by electrolysis of their fused salts are highly:

  1. electropositive 

  2. electronegative

  3. depends on temperature

  4. depends on impurities in the metal


Correct Option: A

You may be "shocked" to discover that metals are good conductors of electricity. Which of the following statements best explains why metals behave in this way?

  1. Metallic bonding can be described as an "electron sea" with mobile valence electrons.

  2. Metals tend to have higher densities than nonmetals.

  3. Metals tend to have higher melting points than nonmetals.

  4. Metals tend to have rather large values for electronegativity.


Correct Option: A
Explanation:

Ans : (A) Metallic bonding can be described as an 'Electron Sea' with mobile valence Electron.

Note: - In metals, the outer Electrons of atom belong to a 'cloud' of delocalised $e^{\ominus}$. They are no longer firmly held by a specific atom, but instead they can move freely through the lattice of positive metals ions. $\therefore$ Metals are good conductor of Electricity.

You have three solids. One is a metal; one is an ionic compound; one is a molecular/covalent compound. You test all three solid samples to identify their bonding.

Sample Appearance Melting Point $(^{\circ}C)$ Conductivity
A Shiny $962$ conductive
B Crystalline $801$ conductive in aqueous solution
C Powdery $186$ not conductive

Based on this data, identify the type bonds present in each sample.

  1. Sample A is a metal.

    Sample B is a salt.

    Sample C is a molecule.

  2. Sample A is a molecule.

    Sample B is a metal.

    Sample C is a salt.

  3. Sample A is a salt.

    Sample B is a metal.

    Sample C is a molecule.

  4. Sample A is a molecule.

    Sample B is a salt.

    Sample C is a metal.


Correct Option: A
Explanation:

Ans : (A) Sample $A$ is metal

(B) Sample $B$ is a salt
(C) Sample $C$ is a molecule
Note : - (1) We know that metal possers shiny properties and it is a good conductor of electricity.
(2) Ionic salt is dissolved in water make an electrically conductive solution. Ionic compound is formed from strong electrostatic interaction between ions which result in a higher melting point.
(3) Molecule do not have free $e^{\ominus}$ to conduct the Electricity.

Molten silver absorbs _________ which is given off on cooling causing violent spurting. This is called splitting of silver and can be prevented by covering the molten metal with a layer of charcoal.

  1. carbon monooxide

  2. carbon dioxide

  3. carbon

  4. charcoal


Correct Option: B
Explanation:

Molten silver absorbs oxygen which is given off on cooling causing violent spurting. This is called splitting of silver and can be prevented by covering the molten metal with a layer of charcoal.

The percent of silver in silver - copper alloy used for jewellery purposes has _______ % silver.

  1. 20

  2. 40

  3. 60

  4. 80


Correct Option: D
Explanation:

The percent of silver in silver - copper alloy used for jewellery purposes has 80 % silver and 20% copper. Silver copper alloy is used in coins, ornaments, silver ware, decoration pieces, etc.

Which of the following is/are true regarding the physical properties of silver?

  1. It is white, lustrous, lightweight metal.

  2. It is very malleable and ductile, coming before gold in this property.

  3. It is poor conductor of heat and electricity.

  4. None of the above.


Correct Option: D
Explanation:

The following  are true regarding the physical properties of silver.
It is white, lustrous, heavy metal.
It is very malleable and ductile, coming next to gold in this property.
It is best conductor of heat and electricity.

An element is sonorous and highly ductile. Under which category would you classify this element? What other characteristics do you expect the element to possess?

  1. Metal

  2. Non-Metal

  3. Metalloid

  4. Semi-conductor


Correct Option: A
Explanation:

Metal

Malleable high melting and boiling point, lustrous hard, high density and a good conductor of heat and electricity.