Chemistry

Periodic Classification and Elements

1,176 Questions

Periodic classification organizes chemical elements based on atomic structure, periodic laws, and elemental properties. It covers historical classification systems, electron configurations, and periodic trends. Test takers preparing for chemistry sections will find these questions crucial for mastering fundamental element properties and atomic interactions.

Periodic table structureAtomic orbitalsElement identificationPeriodic laws

Periodic Classification and Elements Questions

Multiple choice

How does ionisation energy change as we go down a group in the modern periodic table?

  1. Increases

  2. Decreases

  3. No change

  4. First increases and then decreases
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Ionisation energy goes on decreasing down a group. It is due to increase in the distance between the valence electrons and the nucleus. As the atomic size increases down a group, the force of attraction between the nucleus and the valence electrons decreases. Therefore, the energy required to remove the electrons, i.e. ionisation energy, goes on decreasing.

Multiple choice

Among the elements of group 17, the element which is the most reactive is

  1. F

  2. Cl

  3. Br

  4. I
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Fluorine is the most reactive element of group 17. Fluorine is much more reactive because it has the highest electronegativity of all the elements (4.0). It wants an electron the most; so it will practically rip off electrons from other elements just to fill its shell. This also leads to why fluorine is never seen in its elemental form naturally because of its extreme reactivity.

Multiple choice

Inner transition elements include _____________.

  1. lanthanides

  2. metalloid

  3. actinides

  4. option 1 and 2

  5. option 1 and 3
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Yes, it is the correct answer. The f-block transition elements are sometimes known as inner transition elements. The first row of them is called the lanthanides or rare earths. The second row consists of the actinides.

Multiple choice

The term "transition elements" most commonly refers to the d-block transition elements. Which of the following elements does not belong to this group?

  1. Iron (Fe)

  2. Copper (Cu)

  3. Gold (Au)

  4. Aluminium (Al)

  5. Silver (Ag)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Yes, it is the correct answer. Al is not a transition element. The transition elements include the important metals: iron, copper and silver. Iron and titanium are the most abundant transition elements.

Multiple choice

Which of the following statements regarding the metallic character trend in the periodic table is true?

  1. Ability to lose electrons decreases along the period from left to right.

  2. Ability to form ionic chlorides decreases along the period from left to right.

  3. Ability to form basic oxides decreases along the period from left to right.

  4. Ability to displace hydrogen from dilute acids decreases along the period from left to right.

  5. All of these
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Yes, all are correct.

Multiple choice

Which of the following statements is/are true, regarding the trends in a periodic table? (a) Valency increases on moving from top to bottom in a group. (b) Metallic properties decreases on moving from left to right in a period. (c) Atomic mass increases on moving from top to bottom in a group. (d) Electronegativity increases on moving from left to right in a period.

  1. only a

  2. only b

  3. both a and b

  4. b, c and d

  5. both b and d
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Yes, it is correct. All the three options are true. Atoms of metals tend to lose electrons, the strong attraction does not allow loss of electrons, causing metallic character to decrease from left to right in a period. Atomic mass increases from top to bottom and across a period the electronegativity increases.

Multiple choice

Which of the statement/s is/are incorrect regarding the trends in the periodic table?

  1. Number of valence electrons remains the same while moving from top to bottom in a group.

  2. Number of valence electron increases while moving from left to right in a period.

  3. Valency remains the same on moving from top to bottom in a group.

  4. Valency increases while moving from left to right in a period.

  5. Atomic radius increases on moving from top to bottom in a group and decreases on moving from left to right in a period.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Yes, it is the incorrect statement. Valency first increases up to 4 on moving from left to right in a period and then decreases up to zero.