Chemistry · Science General

Periodic Table and Elements

421 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.