The correct answer is B) One atom of calcium and two atoms of chlorine. I just had the same question on my 9th grade science test today. I hope I didn't give the answer to you too late and I hope it helps you out
Answer:
a)The approximate radius of the nucleus of this atom is 4.656 fermi.
b) The electrostatic force of repulsion between two protons on opposite sides of the diameter of the nucleus is 2.6527
Explanation:

= Constant for all nuclei
r = Radius of the nucleus
A = Number of nucleons
a) Given atomic number of an element = 25
Atomic mass or nucleon number = 52


The approximate radius of the nucleus of this atom is 4.656 fermi.
b) 
k=
= Coulombs constant
= charges kept at distance 'a' from each other
F = electrostatic force between charges


Force of repulsion between two protons on opposite sides of the diameter



The electrostatic force of repulsion between two protons on opposite sides of the diameter of the nucleus is 2.6527
Answer:
5N
Explanation:
Given parameters:
Original length = 22cm
Spring constant, K = 50N/m
New length = 32cm
Unknown
Force applied = ?
Solution:
The force applied on a spring can be derived using the expression below;
Force = KE
k is the spring constant
E is the extension
extension = new length - original length
extension = 32cm - 22cm = 10cm
convert the extension from cm to m;
100cm = 1m;
10cm will give 0.1m
So;
Force = 50N/m x 0.1m = 5N
When the resultant force is not equal to zero termed an unbalanced force. By procedures 4 and 5 students observe an unbalanced upward force on Box 1. Hence option 1 is right for the problem.
<h3>What is an unbalanced force?</h3>
The forces operating on a body are known as unbalanced forces when the resulting force exerted on it is not equal to zero.
Unbalanced forces acting on the body, causing it to modify its state of motion. To further grasp the nature of imbalanced forces.
<h3 />
The following reasons by which we can understand the unbalanced force caused by the box.
Due to these two reasons, books will move up.
By adding another mass to box 2. The box becomes lighter. As the box becomes lighter the gravity force acting on the box will be less due to which the box easily can move up.
By removing the two masses from box 1. Due to which other become heavier other becomes heavier pulling it down causing box 1 one to go up.
Hence by procedures 4 and 5 students observe an unbalanced upward force on Box 1. Hence option 1 is right for the problem.
To learn more about the unbalanced force refer to the link;
brainly.com/question/227461
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