Tag: composition of matter

Questions Related to composition of matter

By dropping a drop of water on a glowing electric bulb, it bursts. This is because glass is a _________.

  1. good conductor of heat

  2. bad conductor of heat

  3. transparent substance

  4. good conductor of electricity


Correct Option: B
Explanation:

1) The glass is actually an insulator. 

2) It doesn't allow the flow of electrons easily from atom to atom, as seen in substances like copper, and other metals which are excellent conductors of both heat and electricity. 

3) Insulators have electrons that are held tightly which means they aren't shared between other atoms.

Which of the following is a property of nonmetals?

  1. Low densities

  2. Low melting points

  3. Poor conductor of electricity

  4. All the three


Correct Option: D
Explanation:
Non metals are poor conductor of electricity, low densities, low melting points, non lustrous, brittle in nature, non ductile and not malleable in nature.
So, answer is D.

Which of the following are properties of non-metals?

  1. Low melting point

  2. Poor conductor of electricity

  3. Low densities

  4. All of these


Correct Option: D
Explanation:
Common Properties of non-metals-
  • High ionization energies.
  • High electronegativities.
  • Poor thermal conductors.
  • Poor electrical conductors.
  • Brittle solids - not malleable  or ductile.
  • Little or no metallic lustre.
  • Gain electrons easily.
  • Dull, not metallic-shiny, although they may be colorful.
  • Low melting point and densities.
  • Lower melting points and boiling point than the metals.

The non-metal having shining surface is:

  1. sulphur

  2. phosphorus

  3. iodine

  4. carbon


Correct Option: C
Explanation:

It's because going down the group the size of the atom increases because of the shielding effect due to which the interaction between the atom and the outermost electron decreases.

 So these electrons on the surface of iodine become excited by absorbing heat energy from light. so when they release this energy and come to their normal state, they emit this light so it appears that they have a shining surface.

So, the correct option is $C$

At room temperature liquid non-metal is 

  1. Carbon

  2. Bromine

  3. Mercury

  4. Iodine


Correct Option: B
Explanation:

At room temperature liquid non-metal is bromine.

Generally, non-metals are not good conductors of electricity. 

Which of the following is a good conductor of electricity?

  1. Diamond

  2. Graphite

  3. Buckminster fullerene

  4. Sulphur


Correct Option: B
Explanation:

Graphite has a layered planar structure. Carbon atoms in the plane are bonded covalently with only three of the four potential bonding sites. The fourth electron is free to migrate in the plane making graphite electrically conductive.

Bromine is the only liquid non-metal.

  1. True

  2. False


Correct Option: A
Explanation:
Bromide is only liquid non metal ,mercury is liquid metal crallium is liquid metal.

Iodine is a non-metal which has metallic lusture.

  1. True

  2. False


Correct Option: A
Explanation:

Its because going down the group the size of the atom increases because of shielding effect due to which the interaction between the atom and the outermost electron decreases so these electrons on the surface of iodine become excited by absorbing heat energy from light so when they release this energy and come to their normal state, they emit this light so it appears that they have lustrous surface.

A non-metal which is a good conductor of electricity is:

  1. graphite

  2. hydrogen

  3. sodium

  4. mercury


Correct Option: A
Explanation:

1) Graphite is soft and slippery because there are only weak intermolecular forces between its layers. Graphite is a good conductor of heat and electricity.

2) Graphite can conduct electricity because of the delocalised (free) electrons in its structure.

3) These arise because each carbon atom is only bonded to 3 other carbon atomsHowever, in diamond, all 4 outer electrons on each carbon atom are used in covalent bonding, so there are no delocalised electrons.

4) These electrons in graphite are free to move through the structure.

Chlorine is greenish yellow gas.

  1. True

  2. False


Correct Option: A
Explanation:

It is a pale green gas and is used in cleaning products. Chlorine is an greenish-yellow gaseous element. Its atomic number is 17, and is one of the class called halogens in the periodic table. Large concentration of chlorine are dangerous.