Tag: structure of the atom

Quizzes (7) Questions (35)

Questions Related to structure of the atom

Multiple choice chemistry structure of the atom electronic configuration and valency electron configuration periodic trends in physical properties

An atom of each element has a definite combining capacity called : 

  1. valency

  2. affinity

  3. bonding

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

An atom of each element has a definite combining capacity called its valency.

For example Na has electronic configuration 2,8,1 
So, valency is 1 as after losing one electron it will have stable octet.

Multiple choice chemistry structure of the atom electronic configuration and valency electron configuration periodic trends in physical properties

The valency of nitrogen in nitrogen dioxide is:

  1. 1

  2. 2

  3. 3

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

$(D)$  $ 4$


$Sol. $  let the valency of nitrogen in be $ x$. 
           valency of oxygen = $ -2 $
          For $NO _2 $ it will be ,
                                $ x + 2 \times(-2) = 0 $
                                 $ x = +4 $
Hence, the valency of nitrogen in $ NO _2$ is $ +4 $. 

Multiple choice chemistry structure of the atom electronic configuration and valency electron configuration periodic trends in physical properties

Valency of magnesium and oxygen in $MgO$ is:

  1. one and one

  2. two and two

  3. one and two

  4. two and one
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Ans. $(B)$ $(two$ $and$ $two)$

This is because magnesium loses two electrons to have an octet and oxygen gains two electrons to have an octet. The final formula of magnesium oxide is ${MgO}$. So, the valencies magnesium and oxygen in $ {MgO}$ are $2$ and $2$ .
Multiple choice chemistry structure of the atom neutrons discovery of neutrons structure of atoms

Which of the following statements is false?

  1. Proton has a positive charge

  2. Neutron has no charge

  3. Electrons are found in regions of the atom called orbitals

  4. Electrons has a greater mass than the protons

  5. Protons and neutrons form the nucleons of the atom
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Electron has less mass. A proton and a neutron have effectively the same mass. A proton (or a neutron) has approximately 1837 times more massive than an electron.
Multiple choice chemistry structure of the atom neutrons discovery of neutrons structure of atoms

$ _{7}{X}^{15}$ and $ _{8}{Y}^{15}$ differ in

  1. Physical properties

  2. Chemical properties

  3. Number of neutrons

  4. Number of nucleons
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The option (C) is the correct answer.
$\displaystyle _{7}{X}^{15}$ and $\displaystyle _{8}{Y}^{15}$ differ in number of neutrons.
Number of neutrons for $\displaystyle _{7}{X}^{15} = 15-7=8$
Number of neutrons for $\displaystyle _{8}{Y}^{15}=15*8=7$
Note: Number of neutrons $\displaystyle =$ mass number $\displaystyle -$ atomic number.

Multiple choice chemistry structure of the atom neutrons discovery of neutrons structure of atoms

Number of neutrons present in $1.7$ g of ammonia is:

  1. $0.8N _A$
  2. $0.7N _A$
  3. $0.652N _A$
  4. $0.52N _A$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Let us consider the problem.
For, moles of $N{H _3} = \frac{{1.7}}{{17}} = 0.1$
Let the Neutrons in 1 molecules of $N{H _3} = 7 + 3 \times 0 = 7$
Hence,
Number of Neurons $= 0.1 \times {N _A} \times 7$
The correct answer is $0.7{N _A}$