Tag: introduction to non-metals

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Multiple choice chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

 Silica is added to roasted copper ore during extraction in order to remove:

  1. cuprous sulphide

  2. ferrous oxide

  3. ferrous sulphide

  4. cuprous oxide
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Silica is added during smelting in order to remove iron oxides from copper sulphide and oxides. During roasting the iron sulfides react with oxygen (in air or oxygen enriched air) to produce iron oxides (mainly as $FeO$, but with some magnetite $(Fe _3O _4))$ and sulfur dioxide. 
Copper sulfide and iron oxide can mix, but when sufficient silica is added, a separate slag layer is formed. 
The slag forming reaction is:
$FeO + SiO _2 \rightarrow FeO.SiO _2$
Slag is less dense than matte, so it forms a layer that floats on top of the matte.
Multiple choice chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

Which of the following is used for decorating sweets?

  1. Copper foil

  2. Aluminium foil

  3. Silver foil

  4. All of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Silver foil is used for decorating sweets called Vark,  or varak (also a silver leaf, German paper) is any leaf composed of pure metals, typically silver but sometimes gold, used on South Asian sweets. The silver is edible, though flavourless.


Hence, the correct option is $C$.

Multiple choice chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

Heat conduction is the property of __________.

  1. Non-metals

  2. Metals

  3. Metalloids

  4. All of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Heat conduction is the property of metals. In metals, valance electron is free to flow among the atoms. Because of that metals are such good conductors of electricity. These electrons can also carry energy in the form of heat and thus the metals are conductors of heat.


Hence, the correct option is $B$

Multiple choice chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

Read the following statements and answer as true or false.
Metals occur in nature only as free elements.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Given statement is false. Very few elements occur in the free state - example: gold, platinum etc. The rest of the elements are found in the combined state as compounds such as carbonates,sulphides, oxides etc.

Multiple choice chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

Which of the following is not the allotropic form of sulphur?

  1. Roll sulphur

  2. Monoclinic sulphur

  3. Plastic sulphur

  4. Rhombic sulphur
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Allotropes are defined as chemical elements which exist in two or more different forms, in the same physical state.

or allotropes are defined as different structural modifications of an element, the atoms of the element are bonded together in a different manner.
At present, about 30 well-characterized sulphur allotropes are known.

Commonly known allotropes of sulphur are:

  1. Rhombic sulphur
  2. Monoclinic sulphur
  3. Plastic sulphur ( also known as gamma-sulphur)

Roll sulphur is not the allotropic form of sulphur.

Multiple choice chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

Which of the following statement(s) is/are true?

  1. Among all the naturally occurring elements, around 80% are metals

  2. Non-metals are more abundant than metals

  3. Sodium and potassium are soft like wax

  4. Bromine is a reddish brown liquid at room temperature
Reveal answer Fill a bubble to check yourself
A,C,D Correct answer
Explanation

In general, elements located in the left two-thirds of the periodic table are metals, and the non-metals are on the right side of the table. 


There are about 98 elements in the periodic table that are found naturally. among which 10 are found in traces. Out of these 98 elements, 13 are non-metals and are metalloids. Thus, 78 are metals out of 98. hence about 80 per cent of all the naturally occurring elements are metals.

Sodium and potassium metals are soft and can be easily cut by a knife.

Bromine is a non-metal and is reddish-brown in colour as liquid and as gas.

Therefore, option $A, C, D$ are correct.

Multiple choice chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

Metals and non- metals are separated by a zig - zag line.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

True.

The elements that touch the zigzag line are classified as metalloids. The elements in the far upper right corner are classified as nonmetals. Elements in the first group have one outer shell electron and are extremely reactive. They are called alkali metals.