Tag: structure of atoms

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Multiple choice chemistry what is inside atom discovery of neutrons structure of atoms discovery of subatomic particles

Who determined the mass of a neutron?

  1. John Dalton (early 1800's)

  2. Ernest Rutherford (1911)

  3. Niels Bohr (1913)

  4. James Chadwick (1932)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The presence of neutron and its mass was determined by James Chadwick. Neutron was discovered by bombarding $\alpha-$particles on $Be$. On doing so, highly energetic beam of radiation was observed by Chadwick. Thus mass of neutron was determined by James Chadwick.

Multiple choice chemistry what is inside atom discovery of neutrons structure of atoms discovery of subatomic particles

Whose experiment proved the existence of the nucleus?

  1. John Dalton (early 1800's)

  2. Ernest Rutherford (1911)

  3. Niels Bohr (1913)

  4. James Chadwick (1932)
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The $\alpha-$ ray scattering-gold foil experiment by Ernest Rutherford gave substantial evidence for  existence of nucleus in $1911$. Thus the existence of nucleus was proved by Rutherford's experiment.

Multiple choice chemistry what is inside atom discovery of neutrons structure of atoms discovery of subatomic particles

Neutron was discovered by:

  1. J.J. Thomson

  2. Chadwick

  3. Rutherford

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

 Neutron was discovered by Chadwick.
To overcome the failure of proton electron hypothesis, Rutherford, in 1920, proposed the existence of neutral particle made from close combination of proton and electron. He named it neutron.
In 1932, Lord Chadwick proved the existence of neutron by bombarding lighter elements (boron and beryllium) with alpha particles which resulted in the emission of highly penetrating neutral radiation.

Multiple choice chemistry what is inside atom discovery of neutrons structure of atoms discovery of subatomic particles

The neutron is a neutral (non-electrical) particle in the centre of the atom. It was discovered when a tiny piece of the metal, beryllium, was bombarded with alpha particles. This discovery was made by:

  1. Chadwick

  2. Rutherford

  3. Niels Bohr

  4. Enrico Fermi
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
In 1930, it was discovered that Beryllium, when bombarded by alpha particles, emitted a very energetic stream of neutral radiation. In 1932, Chadwick proposed that neutral radiation consists of a new type of neutral particles - neutrons.
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.