Structure of the Atom — Science STD 9 — Question

What prevents an atom from being collapsed?

In which of the following conditions, the distance between the molecules of hydrogen gas would increase?

1. Increasing pressure on hydrogen contained in a closed container.
2. Some hydrogen gas leaking out of the container.
3. Increasing the volume of the container of hydrogen gas.
4. Adding more hydrogen gas to the container without increasing the volume of the container.

1. (i) and (ii)
2. (i) and (iv)
3. (ii) and (iii)
4. (ii) and (iv)

Isotopes have same____but different____.

The atomic number of an element is 13 and its mass, mass number is 27. The correct order representing the number of electrons, protons and neutrons respectively in this atom is:

There are four elements P, Q, R and S having atomic numbers of 4, 18, 10 and 16 respectively. The element which can exhibit covalency as well as electrovalency will be:

1. P.
2. Q.
3. R.
4. S.

An ionic compound will be formed by the combination of one of the following pairs of elements. This pair of elements is:

Arun has prepared 0.01% (by mass) solution of sodium chloride in water. Which of the following correctly represents the composition of the solutions?

1.008 grams of hydrogen combines with 35.453 g of chlorine to form 36.463 g of a pure compound (hydrogen chloride). Dalton's explanation for this experimental fact might be: 

Symbol of Cadmium is: