Tag: physical properties of non-metals

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Multiple choice chemistry chemistry of non-metals physical properties of non-metals uses of metals and non metals physical properties of metals and non-metals

Platinum metal can be dissolved in:

  1. hot conc. HCl
  2. hot conc. $HNO _3$
  3. hot dil. $H _2SO _4$
  4. a mixture of conc. HCl and $HNO _3$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
  • Traditional aqua regia is a mixture of concentrated nitric and hydrochloric acids in a ratio of 1:3 that can dissolve noble metals such as gold, platinum and palladium, even though the metals are not soluble in either acid alone.
  • Hence option D is correct answer.
Multiple choice chemistry chemistry of non-metals physical properties of non-metals uses of metals and non metals physical properties of metals and non-metals

The most reactive metal among the following is:

  1. Fe

  2. Pt

  3. Ni

  4. Co
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
The reactivity series is sometimes quoted in the strict reverse order of standard electrode potentials, when it is also known as the "electrochemical series":

$Li > Cs > Rb > K > Ba > Sr > Na > Ca > Mg > Be > Al > H( water) > Mn > Zn > Cr > Fe > Cd > Co$
$ > Ni > Sn > Pb > H(in acids) > Cu > Fe(+3) > Hg > Ag > Pd > Ir > Pt > Au $

So, according to this series, Iron is most reactive than $Pt, Ni, Co$
Multiple choice chemistry chemistry of non-metals physical properties of non-metals uses of metals and non metals physical properties of metals and non-metals

Arrange $Si, Be, Mg, Na$ and $P$ in the increasing order of metallic character:

  1. $P<Be<Si<Mg<Na$
  2. $P<Si<Be<Mg<Na$
  3. $Si<P<Mg<Na<Be$
  4. $Na<Mg<Be<Si<P$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

metallic character increases down the group and decreases along the period as we move left to right. Hence the order of increasing metallic character is 

P to Na.

Multiple choice chemistry chemistry of non-metals physical properties of non-metals uses of metals and non metals physical properties of metals and non-metals

In vapour state a metal is mono atomic.

  1. True

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

There are no definitive chemical bonds between two metal atoms in a lattice. They all are held together by the so-called metallic bond. The valence electrons are not shared between metal atoms. Hence they exist as a single metal atom in their lattice unit. 

However we need to apply so much energy to convert it into vapour . And when these change to vapour then no any electron is shared between any metal atom and stay in monoatomic.
When the energy is lowered these again form lattices.

Multiple choice chemistry chemistry of non-metals physical properties of non-metals uses of metals and non metals 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
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

Multiple choice chemistry chemistry of non-metals physical properties of non-metals uses of metals and non metals physical properties of metals and non-metals

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
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

Multiple choice chemistry chemistry of non-metals physical properties of non-metals uses of metals and non metals physical properties of metals and non-metals

A metal which is lighter than water is:

  1. lithium

  2. gold

  3. silver

  4. iron
Reveal answer Fill a bubble to check yourself
A Correct answer
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.
Multiple choice chemistry chemistry of non-metals physical properties of non-metals uses of metals and non metals physical properties of metals and non-metals

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
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Highly electropositive metals (like alkali and alkaline earth metals) have very negative standard reduction potentials, making them difficult to reduce by chemical means. Electrolysis of their fused salts is the standard industrial method for their extraction.

Multiple choice chemistry chemistry of non-metals physical properties of non-metals uses of metals and non metals physical properties of metals and non-metals

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.
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

Multiple choice chemistry chemistry of non-metals physical properties of non-metals uses of metals and non metals physical properties of metals and non-metals

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.
Reveal answer Fill a bubble to check yourself
A Correct answer
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.