Question 1 :
The element with atomic number 56 is likely to have the same outer shell configuration as the element with atomic number __________.
Question 2 :
<span>On the basis of Rutherford's model of an atom, which sub-atomic particle is present in the nucleus of an atom?</span>
Question 3 :
Which of the following is the correct atomic number of Fluorine?
Question 5 :
<span><span>Who suggested the distribution of electrons into different orbits of an atom?</span></span>
Question 12 :
What will be the number of protons, neutrons, and electrons present in <span>$^{59}_{27}Co$ respectively,</span>
Question 13 :
Fill in the blank and complete the analogy by choosing correct alternative from the options given.<div>Neon : (2, 8) : : Argon : _________</div>
Question 16 :
In Thomson's model, _________ are embedded in a positively charged 'soup'.
Question 18 :
The total number of electrons in a nitrogen atom and a chlorine atom are $7$ and $17$ respectively. Find the number of valence electrons in them.
Question 19 :
The atomic number of calcium and argon are 20 and 18 respectively, but the mass number of both these elements is 40. What is the name given to such a pair of elements?<br>
Question 23 :
The ratio of the energy of photon of $2000 A^0$ wavelength to that of $4000 A^0$ wavelength is:
Question 27 :
........... are made up of atoms that are held together by chemical bonds.
Question 35 :
Which scientist suggested that the symbols of elements should be made of one or more letters of the names of the elements?
Question 37 :
<div>A substance formed by the reaction of hydrogen and oxygen is called a/an:</div>
Question 39 :
Which of the following substance is made up of only one type of particle?
Question 41 :
Which of the groups below represents the correct relationship in order from smallest (or simplest) to largest (or more complex)?
Question 45 :
When the size of a spherical nanoparticle decreases from $\text {30 nm}$ to $\text {10 nm}$. The ratio surface area/volume becomes:
Question 48 :
The number of gold atoms in 300 mg of a gold ring of 20-carat gold ($Au = 197$: pure gold is 24 carat) is: