Question 1 :
Which of the following correctly represent the electronic distribution in the Mg atom?

Question 2 :
Which of the following statements about Rutherford’s model of atom are correct? (i) considered the nucleus as positively charged (ii) established that the $\alpha$–particles are four times as heavy as a hydrogen atom (iii) can be compared to solar system (iv) was in agreement with Thomson’s model

Question 3 :
Which of the following scientist identified the 'Neutron' in the structure of an atom ?

Question 4 :
Rutherford’s $\alpha$–particle scattering experiment showed that (i) electrons have negative charge (ii) the mass and positive charge of the atom is concentrated in the nucleus (iii) neutron exists in the nucleus (iv) most of the space in atom is empty Which of the above statements are correct?

Question 5 :
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 6 :
Calculate the number of moles of magnesium present in a magnesium ribbon weighing 12 g. Molar atomic mass of magnesium is $24g mol^{-1}$.

Question 9 :
Which of the following correctly represents 360 g of water? (i) 2 moles of $H_2O$ (ii) 20 moles of water (iii) $6.022\times 10^{23}$ molecules of water (iv) $1.2044\times 10^{25}$ molecules of water