Ernest rutherford was a prominent scientist who contributed significantly to the theory of atomic structure. which of the statements are true? select all that apply.(a) rutherford theorized that atoms contain a positively charged region called the nucleus.(b) rutherford devised the plum pudding model to describe the layout of an atom.(c) rutherford disproved the plum pudding model of the atom.(d) rutherford devised the solar system model to describe the layout of the atom.

(A) Rutherford theorized that atoms contain a positively charged region called the nucleus.

(C) Rutherford disproved the plum pudding model of the atom.

(D) Rutherford devised the solar system model to describe the layout of the atom.

Explanation:

Rutherford conducted an experiment in which he took a thin gold particle film on which he passes alpha- particles. He noticed that:

He concluded that:

Most of the space of the atom is empty and in the center of the atom , there is solid mass which is the cause of the alpha particles to come back. He gave the term nucleus to this solid mass.

This prove that Thomson's plum pudding model is incorrect.

Rutherford Model is also known as Planetary model in which the nucleus is the Sun and the electrons revolve around it in orbits.

Hence, all are true except Option (B).

part 1: the half-life of the element is 22 years.

part 2: it will take 132.02 year for the sample to decay from 308.0 g to 4.8125 g.

explanation:

part 1: there are two ways to determine the half life time.

first way: the half life time can be determined directly from its definition as it is the time required for the sample to decay to its half concentration.

from the data the initial concentration was 45.0 g and decayed to its half value (22.5 g) in 22.0 years.

second way: the radio active decay is considered first order reaction so we can use the laws of first order reactions.

k = (1/t) ln (a/a-x), where k is the rate constant of the reaction,

t is the time of the reaction

a is the initial concentration of the reactant

a-x is the remaining concentration at time (t)

a = 45.0 g the initial concentration at t = 0 year.

at t = 22 year, a-x = 22.5 g

then k = (1/22 year) ln (45.0 g/ 22.5 g) = 0.0315 year-1.

the half-life time (t1/2) = ln 2/ k = 0.693/ k =0.693/ 0.0315 = 22 years.

part 2:

using the same law k = (1/t) ln (a/a-x),

using the given data; a = 308.0 g and a-x = 4.8125 g and the calculated k from the part 1 (k = 0.0315 year-1)

t = (1/k) ln (a/a-x) = (1/0.0315) ln (308.0/ 4.8125) = 132.02 years