In 1917, Rutherford discovered something new, he bombarded alpha particles on nitrogen gas and noticed that occasionally an oxygen atom is produced. From this he concluded that the alpha particles removes proton from the nucleus (positively charged particle). He named this playing with marbles and he become the first one to split an atom. Thus, by bombarding nitrogen with alpha particles, he observed the production of oxygen, a different element.
Therefore, he said bombarding atoms with particles is similar to playing with marbles.
Answer:
The proton and electrons are equal,
15protons and 15electrons
Explanation:
An atom is the smallest electrical neutral particle of an element so it means that every atom have same number of protons and electrons.
Answer : The equilibrium concentration of
in the solution is, 
Explanation :
The dissociation of acid reaction is:

Initial conc. c 0 0
At eqm. c-x x x
Given:
c = 

The expression of dissociation constant of acid is:
![K_a=\frac{[H_3O^+][C_6H_5COO^-]}{[C_6H_5COOH]}](https://tex.z-dn.net/?f=K_a%3D%5Cfrac%7B%5BH_3O%5E%2B%5D%5BC_6H_5COO%5E-%5D%7D%7B%5BC_6H_5COOH%5D%7D)

Now put all the given values in this expression, we get:
![6.3\times 10^{-5}=\frac{(x)\times (x)}{[(7.0\times 10^{-2})-x]}](https://tex.z-dn.net/?f=6.3%5Ctimes%2010%5E%7B-5%7D%3D%5Cfrac%7B%28x%29%5Ctimes%20%28x%29%7D%7B%5B%287.0%5Ctimes%2010%5E%7B-2%7D%29-x%5D%7D)

Thus, the equilibrium concentration of
in the solution is, 
<h3><u>Answer</u>;</h3>
Concave Lenses
<h3><u>Explanation</u>;</h3>
- A concave lens is thin in the middle and thick at the edges, such that it seems to cave inwards. It spreads light rays apart producing an image smaller than the actual object.
- <em><u>Images formed by a concave lens are virtual, upright, reduced in size and located on the same side of the lens as the object. Diverging lenses or concave lens always produce images that share these characteristics. The location of the object does not affect the characteristics of the image. </u></em>
Given by the name of these compounds, they are formed if one or more hydrogen atoms are substituted for halogens
X = Cl, Br, I, F