Allied solutions

Allied solutions

Grade 7

Metals and Non-Metals | Exercise

Question 10

Q10) State what are metalloids. Name the elements recognised as metalloids. Compare the properties of metalloids with those of metals. State the uses of three different metalloids.

Solution :

Metalloids are elements that show physical and chemical properties of metals and non metals both.

Elements like boron, silicon, germanium, arsenic, antimony, tellurium are recognized as metalloids.

Properties of metals vs metalloids.

  1. State - Metals are solid at room temperature except mercury which is liquid. Metalloids are generally solid at room temperature.
  2. Lustre - Metals are shiny and reflect light from their surface. Metalloids have metallic lustre but show properties of weak non-metals.
  3. Conductivity - Metals are good conductors of heat and electricity while metalloids are semiconductors of electricity and average transmission of heat.
  4. Malleability and ductility - Metals can be drawn into sheets and wires but metalloids like silicon are not malleable and ductile.

Use of metalloids

  1. Boron is used as an insecticide and a fire retardant.
  2. Silicon gel is applied to bum patients and to absorb moisture.
  3. Arsenic is used for certain medicinal purposes.
  4. Antimony is used as an antiparasitic drug.
  5. Germanium is used as a semiconductor in cell phones.

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Question 10

Q10) State what are metalloids. Name the elements recognised as metalloids. Compare the properties of metalloids with those of metals. State the uses of three different metalloids.

Solution :

Metalloids are elements that show physical and chemical properties of metals and non metals both.

Elements like boron, silicon, germanium, arsenic, antimony, tellurium are recognized as metalloids.

Properties of metals vs metalloids.

  1. State - Metals are solid at room temperature except mercury which is liquid. Metalloids are generally solid at room temperature.
  2. Lustre - Metals are shiny and reflect light from their surface. Metalloids have metallic lustre but show properties of weak non-metals.
  3. Conductivity - Metals are good conductors of heat and electricity while metalloids are semiconductors of electricity and average transmission of heat.
  4. Malleability and ductility - Metals can be drawn into sheets and wires but metalloids like silicon are not malleable and ductile.

Use of metalloids

  1. Boron is used as an insecticide and a fire retardant.
  2. Silicon gel is applied to bum patients and to absorb moisture.
  3. Arsenic is used for certain medicinal purposes.
  4. Antimony is used as an antiparasitic drug.
  5. Germanium is used as a semiconductor in cell phones.

Still have questions? Our expert teachers can help you out

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subject-cta
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