Question 1 :
In a sample of ethyl ethanoate ($CH_{3}COOC_{2}H_{5}$) the two oxygen atoms have the same number of electrons but different number of neutrons. Which of the following is the correct reason for it?

Question 2 :
In the Thomson’s model of atom, which of the following statments are correct? (i) the mass of the atom is assumed to be uniformaly distributed over the atom (ii) the positive charge is assumed to be uniformaly distributed over the atom (iii) the electrons are uniformaly distributed in the positively charged sphere (iv) the electrons attract each other to stabilise the atom.

Question 3 :
<img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d2b2f59b460d7261f60c.JPG' /> Find out the valency of atoms represented by the figure.

Question 7 :
Identify the $Mg^{2+}$ ion from the figure where, n and p represent the number of neutrons and protons respectively.

Question 8 :
In response to a question, a student stated that in an atom, the number of protons is greater than the number of neutrons, which in turn is greater than the number of electrons. Do you agree with the statement ? (Yes/No)

Question 10 :
Calculate the number of neutrons present in the nucleus of an element X which is represented as $_{15}^{31}X$.

Question 11 :
One electron is present in the outer most shell of the atom of an element X. What would be the value of charge on the ion formed if this electron is removed from the outermost shell ?

Question 12 :
One electron is present in the outer most shell of the atom of an element X. What would be the nature of charge on the ion formed if this electron is removed from the outermost shell ?

Question 13 :
The ratio of the radii of hydrogen atom and its nucleus is ~ $10^{5}$. Assuming the atom and the nucleus to be spherical, what will be the ratio of their sizes ?

Question 14 :
Rutherford’s 'alpha ($\alpha$) particles scattering experiment’ resulted in to discovery of _______.

Question 15 :
Calculate the number of neutrons present in the nucleus of an element X which is represented as $_{15}^{31}X$.

Question 17 :
<img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d2b2f59b460d7261f60c.JPG' /> Find out the valency of atoms represented by the figure.

Question 18 :
Which of the following scientist identified the 'Indivisibility of atoms' in the structure of an atom ?

Question 19 :
In response to a question, a student stated that in an atom, the number of protons is greater than the number of neutrons, which in turn is greater than the number of electrons. Do you agree with the statement ? (Yes/No)

Question 20 :
Which of the following scientist identified the 'Neutron' in the structure of an atom ?