Chemistry · Science General

Periodic Table and Elements

406 Questions

The periodic table and elements questions test knowledge of chemical properties, atomic structures, and periodic trends. Topics include alkali metals, transition elements, and ionisation potential. These concepts frequently appear in general science sections of competitive examinations.

Alkali metals propertiesTransition elementsLattice energyIonisation potentialAlkaline earth metals

Periodic Table and Elements Questions

Multiple choice chemistry lattice energy defining lattice energy ionic or electrovalent bond energy cycles

Which has larger lattice energy among $ZnO$ and $NaCl$?

  1. $ZnO$ > $NaCl$
  2. $ZnO$ < $NaCl$
  3. $ZnO$ = $NaCl$

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Lattice Energy is directly proportional to the charge on the ions and inversely proportional to the size of the ions. There are two factors at work here. The main factor is the charge on the ions. In $ZnO$, both positive and negative ions carry two charges. In $NaCl$, they only carry one. The lattice energy is much greater in $ZnO$ than in $NaCl$.

Multiple choice chemistry lattice energy defining lattice energy ionic or electrovalent bond energy cycles

Which shows the highest lattice energy?

  1. $RbF$
  2. $CsF$
  3. $NaF$
  4. $KF$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

$NaF$  shows the highest lattice energy.Smaller the size of cation, more is attraction among ions. The bond between ions of opposite charge is strongest when the ions are small.The lattice energies for the alkali metal halides is therefore, largest.

Multiple choice chemistry lattice energy defining lattice energy ionic or electrovalent bond energy cycles

Based on lattice energy and other considerations which one of the following alkali metal chloride has the highest melting point ?

  1. $KCl$
  2. $RhCl$
  3. $LiCl$
  4. $NaCl$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Comparison of melting points of ionic compounds is generally done by considering the following two factors:

  1. Charge of the cation/anion  : More the charge of cation or anion, stronger will be the forces of attraction between the ions and higher will be the melting point.
  2. Ionic radii: More the distance between ions, lesser will be the strength of the bond giving rise to lesser melting point.                                              
Going by the above rules, the order should have been:
LiCl > NaCl > KC l> RbCl  
(Since charges of the ions are same for each molecule and cationic radius increases down the group.)
But $LiCl$, due to excessive polarization, exhibits high covalent character and is placed last in the order. Hence, the new order would be:
NaCl > KCl > RbCl > LiCl
The other ions, being similar in size to chloride ions, do not undergo much polarization.

Multiple choice chemistry lattice energy defining lattice energy ionic or electrovalent bond energy cycles

Which of the following compounds will have the largest lattice energy?

  1. $AlBr _3$
  2. $CaO$
  3. $LiBr$
  4. $MgBr _2$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Among the cations, $Al^{3+},\ Ca^{2+},\ Li^{+}$ and $Mg^{2+}$, $Al^{3+}$ has the highest charge. Hence, $AlBr _3$ has the highest lattice energy. The lattice energy is directly proportional to the charge on the ion and inversely proportional to the size of the ion. 

Multiple choice chemistry lattice energy defining lattice energy ionic or electrovalent bond energy cycles

We have all heard the phrase "opposites attract but like repels." This is especially true for ionic compounds.
Which one of the following has the largest lattice energy as a result of this attraction?

  1. $LiCl$
  2. $NaCl$
  3. $K _{2}O$
  4. $MgCl _{2}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$LiCl$. $Li^+$ due to its small size and has high polarizing power and attracts the electron cloud of $Cl^-$ towards itself which results in high lattice energy of the molecule.

Multiple choice chemistry lattice energy defining lattice energy ionic or electrovalent bond energy cycles

$MgO$ has a high melting point because due to the highly charged ions, ionic force is strong and lattice energy is........

  1. High

  2. Low

  3. Both are

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

lattice energy is high

In magnesium oxide, both magnesium and oxygen atoms form ions in the lattice. Due to the higher magnitude of the charge on the magnesium and oxygen atoms, the force of attraction between them is very high. This provides them with very high lattice energy and a lot of energy is required to break this lattice. Hence the melting point of $MgO$ is high. Therefore both the statements are correct and statement 2 is the correct explanation for statement 1

Multiple choice chemistry d- and f-block elements comparison of lanthanoids and actinoids actinoids the actinoids

More number of oxidation states are exhibited by the actinoids than by lanthanoids. The main reason for this is:

  1. greater metallic character of the lanthanoids than that of the corresponding actinoids.

  2. more active nature of the actinoids.
  3. more energy difference $5f$ and $6d$-orbitals than that between $4f$ and $5d$-orbitals.
  4. lesser energy difference between $5f$ and $6d$-orbitals than that between $4f$ and $5d$-orbitals.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Actinoids display more oxidation states because of very small energy gap between 5f, 6d and 7s sub shells. Thus, the outermost electrons get easily excited to the  higher energy level giving variable oxidation state.

Hence,option D is correct.
 

Multiple choice chemistry d- and f-block elements comparison of lanthanoids and actinoids actinoids the actinoids

Statement 1: Lanthanides have much less tendency to form complexes than actinides.
Statement 2: Compared to actinides, the lanthanides have relatively larger size of atoms and less nuclear charge.

  1. Statement 1 is True, statement 2 is True, statement 2 is a correct explanation of statement 1.

  2. Statement 1 is True, statement 2 is True, statement 2 is not a correct explanation of statement 1.

  3. Statement 1 is true, Statement 2 is False.

  4. Statement 1 is False, Statement 2 is True.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Because of higher effective nuclear charge and smaller size of atoms the actinides have higher charge density and because of that they have greater tendency to form complexes than the lanthanides.

Multiple choice chemistry d- and f-block elements comparison of lanthanoids and actinoids actinoids the actinoids

The number of oxidation states is exhibited by the actinoids more than by the lanthanide. The main reason for this is:

  1. more energy difference between 5f and 6d orbitals than that between 4f and 5d orbitals.

  2. the lesser energy difference between 5f and 6d orbitals than between 4f and 5d orbitals.

  3. the greater metallic character of the lanthanoids than that of the corresponding actinoids.

  4. more active nature of the actinoids.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Actinides show larger oxidation states due to poor shielding of both $4f$ and $5f$ orbital electrons, as a result, their orbitals have almost similar energy and hence take part in bond formation. Thus the energy gap between $5f, 6d$ and $7s$ become very small.

Multiple choice salts salts and their classification acids, bases and salts chemistry

Which of the following has the highest melting point ?

  1. $BeCl _2$
  2. $LiCl$
  3. $AlCl _3$
  4. $NaCl$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Sodium and magnesium chlorides are solids with high melting and boiling points because of the large amount of heat which is needed to break the strong ionic attractions.
$NaCl$ having the highest melting point as the ionic bond is too strong between $Na$ and $Cl$.

Multiple choice chemistry group 17 group 17 - physical properties physical properties of group 17 elements group 17 elements: the halogen family

Which of the following has highest melting point?

  1. $SrF _{ 2 }$
  2. $BeF _{ 2 }$
  3. $BaF _{ 2 }$
  4. $MgF _{ 2 }$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The melting point of a compound depends on Vander walls force of attraction which increases as molecular size increases, in given compounds Sr atom has the largest size, so vanderwalls force of attraction will be greater in $SrF _2$ and it will have the highest melting point.

Multiple choice chemistry group 17 group 17 - physical properties physical properties of group 17 elements group 17 elements: the halogen family

Which of the following properties of the elements chlorine,bromine and iodine increase with increasing atomic number?

  1. Ionization energy.

  2. Ionic radius.
  3. Bond energy of the molecule ${X _2}$.

  4. Enthalpy of vaporization.
Reveal answer Fill a bubble to check yourself
B,D Correct answer
Explanation

The ionization energies of halogens decrease on moving down the group.

Similarly the bond dissociation energies decrease from chlorine to bromine to iodine.

With increase in the atomic number, the atomic and ionic radii of hydrogen increases from fluorine to iodine.

Also, the melting points and the boiling points increase in the same order.

Hence, the enthalpy of vaporization also increases in the same order.