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

What is the electron configuration for Ca?

  1. [Ar]4s2

  2. [Ar]4s1

  3. [Kr]4s2

  4. 1s2 2s2 2p64s2
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Calcium (Ca) has 20 electrons. The noble gas core [Ar] accounts for 18 electrons, and the remaining 2 electrons occupy the 4s orbital, resulting in [Ar]4s2.

Multiple choice

What are the Elements in Group 1 called?

  1. Alkaline Earth metals

  2. Alkali Metals

  3. Metalloids

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

Group 1 elements are known as the Alkali Metals. They are highly reactive metals with one valence electron.

Multiple choice

What are the elements in Group 2 called?

  1. Alkali Metals

  2. Transition Metals

  3. Alkaline Earth Metals

  4. Other Metals
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Group 2 elements are known as the Alkaline Earth Metals. They are reactive metals with two valence electrons.

Multiple choice some important compounds of magnesium and calcium the s-block elements chemistry

Which of the following element has $2^{nd} IP<1^{st}IP$?

  1. $Mg$
  2. $Na$
  3. $C$

  4. None
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

All three $Mg$, $C$ and $Ne$ have $2nd$ ionisation potential greater than $1st$ ionisation potential. 

This is the general trend shown by most element that $1^{st} IP<2^{nd} IP<3^{rd} IP<$ and so on.
Hence, option D is correct.

Multiple choice

_______ are naturally occurring atoms on Earth.

  1. Organs

  2. Elements

  3. Molecules

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

Elements are pure substances consisting of only one type of atom. They occur naturally on Earth and are the simplest forms of matter.

Multiple choice

Atoms are the building blocks of _______.

  1. matter

  2. elements

  3. life

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

Atoms are the fundamental building blocks of all matter. While they make up life and elements, matter is the most encompassing category.

Multiple choice physics static electricity properties of charges charge properties of charge

$\displaystyle \frac {4}{25}$ Coulomb of charge contains .................. electrons: 

  1. $10^{15}$
  2. $10^{18}$
  3. $10^{20}$

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

Answer is C.

The formula for quantisation of charge is given as q=ne.
where, q is the amount of charge in Coulumbs, n is the number of charges and e is the charge on the electron.
In this case, q=4/25 C
So, e = $1.6\times { 10 }^{ -19 }C$.
n can be calculated as n=q/e = $\frac { 4 }{ 25 } \times [\frac { 1 }{ 1.6\times { 10 }^{ -19 }C } ]\quad =\quad { 10 }^{ 18 }$ which is the number of electrons.
Hence, 4/25 Coulomb of charge contains ${ 10 }^{ 18 }$ electrons:.

Multiple choice physics static electricity properties of charges charge properties of charge

Fill in the blank.

$1$ Coulomb of charge contains_______number of electrons.

  1. $6.25\times 10^{18}$
  2. $3.125\times 10^{18}$
  3. $6.25\times 10^{12}$
  4. $3.125\times 10^{12}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

As charge is quantized. 

Total charge, $Q = ne$
$1$ coulomb $=ne \implies$ $n$ $= \dfrac{1} {1\cdot6\times10^{-19}}$

 
 $n$ $=6\cdot25\times10^{18}$

Multiple choice physics static electricity properties of charges charge properties of charge

There are $4\times { 10 }^{ 23 }$ atoms in a metal sphere. If one electron is removed from $0.1\%$ of atoms, what will be the charge on the sphere?

  1. $-6.4C$
  2. $64C$
  3. $0.64C$
  4. $-64C$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Given, 

$n=4\times 10^{23}\times 0.1$%

$n=4\times 10^{23}\times \dfrac{0.1}{100}=4\times 10^{20}$

$e=1.6\times 10^{-19}C$

The charge is quantised, $q=ne$

$q=4\times 10^{20}\times 1.6\times 10^{-19}=64C$

The electron is negative charge particle.

So,$q=-64C$

The correct option is D.
Multiple choice physics static electricity properties of charges charge properties of charge

$\displaystyle \frac {4}{25}$ Coulomb of charge contains .......... electrons

  1. $10^{15}$
  2. $10^{18}$
  3. $10^{20}$

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

The formula for quantization of charge is given as q=ne.
where q is the amount of charge in Columbu's, n is the number of charges and e is the charge on the electron.
In this case, q=4/25 C
So, e = $1.6\times { 10 }^{ -19 }C$.
n can be calculated as n=q/e = $\frac { 4 }{ 25 } \times [\dfrac { 1 }{ 1.6\times { 10 }^{ -19 }C } ]\quad =\quad { 10 }^{ 18 }$ which is the number of electrons.
Hence, 4/25 Coulomb of charge contains ${ 10 }^{ 18 }$ electrons.

Multiple choice physics static electricity properties of charges charge properties of charge

The number of electrons for one coulomb of charge are:

  1. $\displaystyle 6.25\times { 10 }^{ 23 }$
  2. $\displaystyle 6.25\times { 10 }^{ 21 }$
  3. $\displaystyle 6.25\times { 10 }^{ 18 }$
  4. $\displaystyle 6.25\times { 10 }^{ 19 }$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

1 electron carries a charge of $1.6 \times 10^{-19}$ coulomb 

So, No.of electron in one coulomb
$\dfrac{1}{1.6 \times 10^{-19}} = \dfrac{10^{19}}{1.6} = 6.25 \times 10^{18}$