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 chemistry p- block elements-ii group 17 elements - general properties group 17 elements group 17 elements - properties

The electronic configuration of four atoms are given in brackets:
L : ($1s^2\,2s^2\,2p^1$);                    M : ($1s^2\,2s^2\,2p^5$);

Q : ($1s^2\,2s^2\,2p^6\,3s^1$);             R : ($1s^2\,2s^2\,2p^2$).

The element that would most readily form a diatomic molecule is :

  1. Q

  2. M

  3. R

  4. L
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

From the electronic configuration given it is clear that element M is 1 short of octet configuration. It belongs to group 17. Group 17 elements exist as diatomic molecules.


So, correct option is B.

Multiple choice chemistry p- block elements-ii group 17 elements - general properties group 17 elements group 17 elements - properties

The table shows some information about elements in Group VII of the Periodic Table. 

Name State at room temperature Colour
Chlorine Gas yellow-green
Bromine liquid brown
iodine ? ?
Astaine solid black

Which information about iodine completes the table?

  1. State - liquid, colour - black

  2. State - liquid, colour - green

  3. State - solid, colour - grey

  4. State - solid, colour - yellow
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
$\text{D) State-solid,Colour-yellow}$
$\text{Iodine is solid at room temperature and appears yellow in low concentrat}$
Multiple choice chemistry p- block elements-ii group 17 elements - general properties group 17 elements group 17 elements - properties

The outer most electronic configuration of the most electronegative element is:

  1. $\mathrm{n}\mathrm{s}^{2}\mathrm{n}\mathrm{p}^{3}$
  2. $\mathrm{n}\mathrm{s}^{2}\mathrm{n}\mathrm{p}^{4}$
  3. $\mathrm{n}\mathrm{s}^{2}\mathrm{n}\mathrm{p}^{5}$
  4. $\mathrm{n}\mathrm{s}^{2}\mathrm{n}\mathrm{p}^{6}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Halogens are most electronegative.


Therefore outer electronic configuration is $ns^{2}\ np^{5}$

Option C is correct.

Multiple choice chemistry p- block elements-ii group 17 elements - general properties group 17 elements group 17 elements - properties

The elements with atomic numbers 9, 17, 35, 53 and 85 belong to noble gases columnz__________.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The atomic number of elements are 9,17,35,53,85.
Electronic configuration of elements will be
9  = 2,7
17= 2,8,7
35= 2,8,18,7
53=2,8,18,18,7
85=2,8,18,18,32,7
The pattern shows that all elements have 7 electron in their outermost valence shell and all these elements belong to halogens.

Multiple choice chemistry p- block elements-ii group 17 elements - general properties group 17 elements group 17 elements - properties

In the third excited state the number of unpaired electrons in chlorine atom is:

  1. 5

  2. 7

  3. 3

  4. 1
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The general electronic configuration of chlorine is $[Ne] 3s^{2} 3p^{5}$

When electrons are excited in chlorine, the electrons enter into 3d subshell then electronic configuration of chlorine is given as:
$[Ne] 3s^{1} 3p^{3} 3d^{3}$
Thus the number of unpaired electrons will be 7.

Multiple choice chemistry basic concepts of chemistry law of multiple proportion law of multiple proportions laws of chemical combination

___________ of elements combine in the ratio of whole numbers to produce a large number of a compound called molecules.

  1. Atom

  2. Ion

  3. Charges

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

Atoms of elements combine in the ratio of whole numbers to produce a large number of compound called molecules
For example, one $C$ atom combines with one $O$ atom to form one molecule of $CO$. Also, one $C$ atom combines with two $O$ atoms to form one molecule of $CO _2$.

Multiple choice chemistry basic concepts of chemistry law of multiple proportion law of multiple proportions laws of chemical combination

Atoms of the same two elements can combine in different ratios to form different compounds.
This is:

  1. law of constant composition

  2. law of multiple proportion

  3. law of reciprocal proportion

  4. law of conservation of mass
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

According to the law of multiple proportion, when two elements combine with each other to form more than one compound, the weights of one element that combines with fixed weight of the other are in the ratio of small whole numbers.

Multiple choice physics electric fields introduction to electrostatic force electric force charging and discharging

Which of the following represents Coulomb's constant?

  1. $k\,=\,\frac{1}{4\times \pi \times e^0}$
  2. $k\,=\,1$ + ($4\times \pi \times e^0$)
  3. $k\,=\,1$ - ($4\times \pi \times e^0$)
  4. $k\,=\,1$ * ($4\times \pi \times e^0$)
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

We know that Coulomb's force, $F=\frac{1}{4\pi \epsilon _0} \frac{q _1q _2}{r^2}$


The Coulomb constant will be  $k=\frac{1}{4\pi\epsilon _0}$

Multiple choice chemistry reactivity series and electrochemistry reactivity series and displacement reactions chemical properties of metals chemical properties of metals and non metals

The reactivity series is a list of metals arranged in the order of their _______ activities.

  1. decreasing

  2. Increasing

  3. chemical

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

The reactivity series is a series of metals, arranged in order of reactivity from highest to lowest. It is used to determine the products of single displacement reactions, whereby metal A will replace another metal B in a solution if A is higher in the series.

Multiple choice chemistry reactivity series and electrochemistry reactivity series and displacement reactions chemical properties of metals chemical properties of metals and non metals

If $A, B, C, D, E, F, G, H, I, J, K$ represents metals in the decreasing order of their reactivity, which one of item is most likely, to occur in a free state in nature?

  1. A

  2. C

  3. J

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

Metal higher in the activity series is said to be more metallic than another which is below and the metals at the top of the activity series are so reactive that they are never found in nature in free state.

Multiple choice botany photosynthesis modern concept of photosynthesis photosystems photosynthesis in higher plants

Photolysis of a water molecule yields

  1. 2 electrons and 4 protons

  2. 4 electrons and 4 protons

  3. 4 electrons and 2 protons

  4. 2 electrons and 2 protons
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Photolysis is part of the light-dependent reactions of photosynthesis. The general reaction of photosynthetic photolysis can be given as 

H2AH2A + 2 photons (light) → 2 e−e− + 2 H+H+ + A

So, the correct option is 'Option D'.

Multiple choice chemistry p- block elements-ii group 16 elements - general properties group 16 elements - trends in chemical properties group 16 elements

A group 16 element exists in the monoatomic state in the metallic lattices. It also exists in two crystalline forms. The metal is:

  1. Po

  2. S

  3. Se

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

polonium has two metallic allotropes, the $\alpha $ atom has the simple cubic structure in a single atom basis at STP and $\beta $ atom of it has rhombohedral structure. Po belongs to group 16.