Test: Atomic Models - Grade 10 MCQ

The formula of gravitational force is given by Gm₁m₂/r². Here G is the gravitational constant, while m₁ and m₂ are the masses and r is the distance between m₁ and m₂. This theory is formulated when classic mechanics is applied to it.

An atom is written in the symbol ZXA. By comparing it to ₁₇Cl³⁷, we get a number of protons as 17 and mass number as 37. Mass number – proton number = neutron number. Number of neutrons is 37 – 17 = 20. No. of protons = No. of electrons = 17.

Protium has only 1 proton, deuterium has one proton and 1 neutron whereas tritium has one proton and two neutrons. They are represented by ₁H¹, ₁D² and ₁T³. Helium has 2 protons and two neutrons, hence can’t consider as an isotope. Isotope means having the same number of protons but differ in the number of neutrons.

In this effect, a thin foil (thickness 100nm) made up of gold and coated with fluorescent ZnS screen which is circular around it. α particles mostly move through the gold foil having zero deflection, a small fraction is deflected and one in twenty thousand turns 180°.

Thomson proposed a model of the atom, in which electrons are embedded to make it as the stable electrostatic arrangement and such that positive charge is equally distributed around a sphere. Mass is assumed to be equally distributed. So. it has different names like plum pudding, watermelon and raisin pudding model.

Isobar is a species of an element having the same mass number but a different atomic number. As per the above question, only ₁₉K⁴⁰ satisfies the conditions of ₁₈Ar⁴⁰ to be its isotope.

Yes, chemical properties of an atom is dependent on a number of electrons in that particular atom, which in turn is decided by the number of protons present in that atom. The number of neutrons has only a small effect on this.

For an element, Atomic number(Z) = number of protons in that atoms = numbers of electrons in that atom; Mass number = number of protons + number of neutrons. So Z = 13 and A = 13 + 14 = 27. Hence that element is Aluminium.

Henri Becquerel discovered that elements emit radiation and termed this phenomenon as radioactivity. Later Curie on research found out about α-rays, β-rays and γ-rays. Later Rutherford concluded that α particles are helium nuclei.

According to the fundamental properties of particles, protons charge is +1.602176×10^-19C. It is a subatomic particle. Rutherford discovered protons. Its elementary charge is 1. Proton’s charge is positive.