Tag: alkali metals

Questions Related to alkali metals

The first ionization energies of alkaline earth metals are higher than those of the alkali metals. This is because:

chemistry group 2 physical properties of alkaline earth metals alkali metals properties of alkaline earth metals

  1. there is increase in the nuclear charge of the alkaline earth metal

  2. there is decrease in the nuclear charge of the alkaline earth metal

  3. there is no change in the nuclear charge

  4. none ofthe above

Show answer
Correct Option: A
Explanation:

As the nuclear charge increases it requires more energy to remove electron(Ionization energy) hence ionization energy will be increased. The first ionization energies of alkaline earth metals are higher than those of the alkali metals. This is because of the increase in the nuclear charge of the alkaline earth metal.

Alkaline earth metal salt are :

chemistry group 2 physical properties of alkaline earth metals alkali metals properties of alkaline earth metals

  1. paramagnetic

  2. diamagnetic

  3. ferromagnetic

  4. all of these

Show answer
Correct Option: B
Explanation:

Alkali earth metals are diamagnetic.

Atoms or elements which are having even number of electrons or  no unpaired electrons are diamagnetic.

Alkaline earth metals are having even number of electrons(Be,Mg,Ca,Sr,Ba,Ra having electrons 4,12,20,38,56 and 88 respectively which are even in number)

Hence option B is correct

Select the correct statement(s) about barium :

chemistry group 2 physical properties of alkaline earth metals alkali metals properties of alkaline earth metals

  1. It shows photoelectric effect.

  2. It is silvery white metal.

  3. It forms $Ba(N _3) _2$ which is used in preparation of green fire.

  4. Its ionization energy is less than radium.

Show answer
Correct Option: B,C,D
Explanation:

A) It shows photoelectric effect.False,becuase it has completely filled s orbital so removal of electron is difficult.

B) It is silvery white metal.True.

C) It forms $Ba(N _3) _2$ which is used in preparation of green fire.True.

D) Its ionization energy is less than radium True.

Hence options B,C & D are correct.

The most lightest alkaline earth metal is:

chemistry group 2 physical properties of alkaline earth metals alkali metals properties of alkaline earth metals

  1. $Be$

  2. $Mg$

  3. $Ca$

  4. $Ba$

Show answer
Correct Option: C
Explanation:

Calcium $(Z=20),$ is the lightest alkaline earth metal, with a density of $1.55 g/cm^3$, lighter than both beryllium and magnesium.

Which of the following has highest melting point?

chemistry group 2 physical properties of alkaline earth metals alkali metals properties of alkaline earth metals

  1. Magnesium

  2. Barium

  3. Calcium

  4. Beryllium

Show answer
Correct Option: D
Explanation:

Beryllium has highest melting point (1560 K).
In fact, the melting point, the boiling point and the ionisation enthalpy of beryllium are highest of all the alkaline earth metals. This is due to small atomic size of beryllium.

Select the incorrect choice: 

chemistry group 2 physical properties of alkaline earth metals alkali metals properties of alkaline earth metals

  1. the solubility of alkaline earth metal's carbonates, sulphates and chromates decreases Be to Be.

  2. the solubility of alkaline earth metal's hydroxides is less than alkali metal hydroxides.

  3. solubility of alkaline earth metal's oxides increases from Be to Ba.

  4. $SO _2$ on passing in lime water turns is milky.

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Correct Option: A

Dehydration of hydrates of halides of calcium, barium and strontium i.e., $CaCl _2.6H _2O,BaCl _2.2H _2O,SrCl _2.2H _2O$ can be achieved by heating. These become wet on keeping in the air. Which of the following statements is correct about these halides?

chemistry group 2 physical properties of alkaline earth metals alkali metals properties of alkaline earth metals

  1. The act as dehydrating agents.

  2. They can absorb moisture from air.

  3. They have tendency to from hydrate which decreases from calcium to barium.

  4. All of the above

Show answer
Correct Option: D
Explanation:

Halides of calcium, barium and strontium act as dehydrating agent as they are hygroscopic in nature. They absorb moisture. Also they have tendency to form hydrate which decreases from $Ca^{2+}$ to $Sr^{2+}$ due to increase in size and decrease in polarization power.

Which of the following metal sulphide is water soluble?

chemistry group 2 physical properties of alkaline earth metals alkali metals properties of alkaline earth metals

  1. $CaS$

  2. $ZnS$

  3. $HgS$

  4. $CdS$

Show answer
Correct Option: A
Explanation:

Calcium sulphide, $CaS$ and zinc sulphide $ZnS$ are slightly soluble in water.
Cadmium sulphide $CdS$ and mercury (II) sulfide are insoluble in water.

Which of the following does/do not impact characteristic colour to the flame?

chemistry group 2 physical properties of alkaline earth metals alkali metals properties of alkaline earth metals

  1. $MgSO _4$

  2. $CaCl _2$

  3. $Sr(NO _3) _2$

  4. $BeCl _2$

Show answer
Correct Option: A,D
Explanation:

$CaCl _2$ has orange colour.
$Sr(NO _3) _2$ has crimson colour flame.


Be and Mg do not impart any colour to the flame due to higher ionization energy and small size.The energy of the flame is not sufficient to excite the electrons to higher energy levels. Hence, they do not impart any characteristic colour to the flame

The correct increasing order of basic nature among Be, Mg, Ca and Sr is :

chemistry group 2 physical properties of alkaline earth metals alkali metals properties of alkaline earth metals

  1. $Be < Ca < Mg < Sr$

  2. $Be < Mg < Sr < Ca$

  3. $Be < Mg < Ca < Sr$

  4. $Ca < Sr < Be < Mg$

Show answer
Correct Option: C
Explanation:
The correct increasing order of basic nature among Be, Mg, Ca and Sr is $Be < Mg < Ca < Sr$.
$Be$ forms amphoteric oxides and hydroxides, whereas other alkaline earth metals form basic oxides and hydroxides. The basicity increases on moving down the group due to increase in the size of the metal ion, decrease in the ionization energy and increase in the electropositive character. This increases the polarity of metal oxygen bond and internuclear distance which in turn increases the ease of formation of ion and the basic character.