Question

2. In an element 'X', 5th electron of 3rd shell is its last electron. In

another element 'Y',7th electron of 3rd shell is its last electron. Then identify 'X' and 'Y'.


3. An element has atomic number 17 and mass number 37.

There are 17 electrons outside the nucleus. Find the number of neutrons in it.


4.What is the atomic number of the element X which has 2

shells, K and L having 2 and 6 electrons respectively?Identify the element X.


5. An old man and a scientist were talking about a deserted house.

The old man was sure that it was haunted by ghosts, but the scientist discarded the view saying no one had ever seen a ghost. The old man was annoyed and challenged the scientist about existence of atoms, sub - atomic particles which also could not be seen. Read the given passage and answer the following questions


(a) Name the three sub - atomic particles and their discoverers.

(b) Whose viewpoint do you support and why?


Please Answer Fast

Answer 1

Answer:

please thanks for the answer

please mark as brainliest answer

Explanation:

2. X is phosphorus and Y is Chlorine.

3. Given - Atomic number of element = 17

Mass number of element = 37

Number of electrons = 17

As we know, number of protons is equal to number of electrons.

so, number of protons = 17

now, Mass number = number of protons + number of neutrons

37 = 17 + number of neutrons

number of neutrons = 37 - 17

number of neutrons = 20

So, the number of neutrons in the nucleus = 20.

4. K = 2, L = 6

Atomic number = Number of protons

= Number of electrons in neutral atom

Atomic number = 2 + 6 = 8

5. (a)(i) Electron - J.J Thomson

(ii) Proton - E. Goldstein

(iii) Neutron - Chadwick

(b) I support scientist's viewpoint because it is based on logic and proven facts. Old man's views are figments of imagination without any scientific truth and are superstitions.