Tag: atom

Quizzes (5) Questions (42)

Questions Related to atom

Multiple choice chemistry atom fundamental particles of an atom the structure of atoms discovery of subatomic particles

Total number of electrons present in $14\ gm$ of nitrogen gas is:

$[N _A = 6\times 10^{23}]$

  1. $6\times { 10 }^{ 23 }$
  2. $4.2\times { 10 }^{ 24 }$
  3. $3\times { 10 }^{ 23 }$
  4. $4.2\times { 10 }^{ 23 }$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

14g of N2 gas is 0.5 moles (molar mass 28g/mol). Each N2 molecule has 14 electrons (7 per nitrogen atom), so 0.5 moles of N2 contains 0.5 * 6 * 10^23 * 14 = 4.2 * 10^24 electrons.

Multiple choice chemistry atom fundamental particles of an atom the structure of atoms discovery of subatomic particles

The approximate atomic weight of electron or positron per mol is:

  1. $5.48\times 10^{-6} g mol^{-1}$
  2. $ 5.48\times 10^{-8} g mol^{-1}$
  3. $5.48\times 10^{-4} g mol^{-1}$

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

Mass of one electron $=9.1\times 10^{-27} g $

So, mass of one mole of electron $=m\times N _o$ $=5.48\times 10^{-4} g mol^{-1}$ as  $N _o = 6.023\times 10^{23}$.

Multiple choice chemistry atom fundamental particles of an atom the structure of atoms discovery of subatomic particles

Rest mass of an electron is $9.11\times 10^{-31}$ kg. Molar mass of the electron is:

  1. $1.50\times 10^{-31}kg$ $mol^{-1}$
  2. $9.11\times 10^{-31}kg$ $mol^{-1}$
  3. $5.5\times 10^{-7}kg$ $mol^{-1}$
  4. $6.02\times 10^{23}kg$ $mol^{-1}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Rest mass of an electron is $9.11\times 10^{-31}kg$.
So, mass of one mole of electron is $9.11\times 10^{-31}\times6.023\times10^{23} = 5.5\times 10^{-7}kg/mole$

Multiple choice chemistry atom fundamental particles of an atom the structure of atoms discovery of subatomic particles

What are nucleons?

  1. the sum of protons and neutrons present in the nucleus.

  2. the number of protons in the nucleus.

  3. the number of neutrons in the nucleus.

  4. the sum of protons, neutrons and electrons present in the nucleus.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A nucleon is one of either of the two types of subatomic particles (neutrons and protons) which are located in the nucleus of atoms.
Only option A correct .

Multiple choice chemistry atom fundamental particles of an atom the structure of atoms discovery of subatomic particles

Find the mass number of sodium having $12$ neutrons.

  1. $22$
  2. $23$
  3. $11$
  4. $12$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The atomic weight is basically a measurement of the total number of particles in an atom's nucleus. Mass number can be found by rounding off an elements atomic mass to the nearest whole number.
Mass Number $=$ (Number of Protons) $+$ (Number of Neutrons)
$= 11 + 12$
$= 23$

Multiple choice chemistry atom fundamental particles of an atom the structure of atoms discovery of subatomic particles

The number of protons is equal to ________ in a neutral atom.

  1. atomic weight

  2. atomic number

  3. number of electrons

  4. both B and C
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The atomic number is the number of protons in an atom of an element. Atoms are electrically neutral. That means that there must be a balance between the positively charged protons and the negatively charged electrons.


Thus, atoms must have equal numbers of protons and electrons.


Hence, the correct option is $\text{D}$