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

Which of the following statements is incorrect?

  1. Both red and grey forms of selenium are non-metallic in nature.

  2. Fluorides are the most stable among the halides of group 16.

  3. O2 and O3 are two allotropic forms of oxygen.

  4. All the hydrides of group 16 act as reducing agents.

  5. H2S is more volatile than water.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

All the hydrides of group 16 elements, except H2O, act as reducing agents and reducing character increases down the group.

Multiple choice

Why does atomic size increase down the group?

  1. Due to increase in nuclear change.

  2. Due to increase in distance between the outermost electrons and nucleus.

  3. Due to increase in force of attraction between outermost electrons and nucleus.

  4. Due to increase in valence electrons.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Atomic size increases down a group due to increase in distance between the outermost electrons and nucleus.

Multiple choice

Which of following statements is false?

  1. Li has smallest size among alkali metal elements.

  2. Li has highest electronegativity among alkali metal elements.

  3. Li is hardest alkali metal.

  4. Li+ has smallest effective size among alkali metal ions in aqueous solution.

  5. LiOH is a weak base.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Li+ being very small in size is heavily hydrated in aqueous solution as compared to other alkali metal ions. The effective size of Li+ ion in aqueous solution is largest.

Multiple choice

Which of the following order of first ionization enthalpies is incorrect?

  1. C>Be>B

  2. Be>Mg>Ca

  3. C>Si>Ge

  4. Li>Na>K

  5. B>Al>Ga
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Unlike expected order of first ionization enthalpies (IE1) i.e., B>Al>Ga, the actual order of IE1 is B>Ga>Al. Because of small atomic size and greater effective nuclear charge, the valence electrons of Ga are held more tightly than Al. Hence, IE1 of Ga is more than that of Al.

Multiple choice

Lithium and sodium are placed in the same group of Mendeleev's periodic table. Which of the following statements is true with regard to lithium and sodium?

(i) They have the same electronic configuration. (ii) The formula of their hydrides is the same. (iii) The formula of their oxides is the same.

  1. (i) and (ii)

  2. (ii)

  3. (iii)

  4. (ii) and (iii)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Lithium and sodium are placed in the same group of Mendeleev's periodic table because they have the same formulas of hydrides (like LiH and NaH) and oxides (like Li2O and Na2O).

Multiple choice

Which of the following elements will have the lowest electronegativity?

  1. Bromine

  2. Chlorine

  3. Fluorine

  4. Iodine
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The given elements belong to group 17 of the periodic table. As we move from top to bottom in a period in the periodic table, the electronegativity decreases because of increase in atomic size. Hence, from all the given elements, iodine will have the lowest electronegativity.