How many electrons will weigh 1 g?
Mass of an electron = 9.11 × 10-31 kg ∴ Mass of 9.11 × 10-31 kg = 1 electron Now, mass of 1g, i.e., 10-3 kg will have electrons =…
An element ‘X’ has mass number 4 and atomic number 2. Write the valency of this element. Will it react with other atoms of different elements?
We know that only valence electrons take part in bond formation with different atoms. In the atom of ‘X’ element there are only two electrons. Since atomic number is 2.…
Explain why chlorine whether as the element or its compounds, always has relative atomic mass of about 35.5.
The relative atomic mass is the average mass of one of the atoms and has to take into account the relative abundances of the various isotopes. Natural chlorine always contains…
Complete the following gaps in the given table:
| Elements | Protons | Electrons | Neutrons | Atomic Number | Mass Number |
| A | – | – | 10 | 8 | – |
| B | 15 | – | – | – | 31 |
| C | 1 | – | – | – | 3 |
| D | – | 11 | 12 | – | – |
We know that the number of protons = Atomic number Number of protons = Number of electrons Mass number = Number of protons + number of neutrons Using these relationships,…
An atom ‘M’ of an element reacts wit oxygen to from M2O3. Calculate the valency of the element ‘M’.
Two atoms of element ‘M’ combine with 3 atoms of oxygen. ∴ Number of oxygen atoms combining with one atom of element ‘M’ = Therefore, the valency of element ‘M’…
Composition of the nuclei of two atomic species ‘X’ and ‘Y’ are given below:
| X | Y | |
| Protons | 8 | 8 |
| Neutrons | 8 | 10 |
(i) Atomic mass of elements ‘X’ = Number of protons + Number of neutrons = 8 + 8 = 16 u (ii) Atomic mass of element ‘Y’ = Number of…
One electron is present in the outermost shell of an element ‘Z’ (a) What will be the nature of this element? (b) What will be value of charge of the ion formed, if this electron is removed from the outermost shell?
(a) Element ‘Z’ will be a metal because it has only one electron in the outermost shell, so it is electropositive. (b) After loss of one electron, ‘Z’ will acquire…
Rutherford’s atomic model was a reasonably good model of structure of atom based on at the famous particle scattering experiment. However, it was subsequently modified by Neils Bohr and later on, by others. The resulting improvements in the understanding of atomic structure have greatly contributed to further scientific advancement. There are many other similar examples in scientific field when original contributors happily accept modifications in their ideas. Answer the following questions based on the above information: (𝒊) Name the scientific values associated with above anecdotes. (𝒊𝒊) Give any example from your life experiences so far which reflects display of such a value by you as an individual. (𝒊𝒊𝒊) In what way such a personal attribute is likely to help you?
(𝑖) Intellectual honesty, open-mindedness, ability to accept failure. (𝑖𝑖) Any examples, say your perception about culture and traditions, your wrong understanding of a physical phenomenon and subsequent change in belief.…
The given figure depicts the atomic structure of an atom of an element ‘X’. Write the following information about the element ‘X’. (a) Atomic number of ‘X’ (b) Atomic mass of ‘X’ (c) Valence electrons (d) Valency of ‘X’ (e) ‘X’ should be metal or non-metal.
(a) Atomic number = Number of protons = 8 (b) Atomic mass = Number of protons + Number of neutrons = 8 + 10 = 18 u (c) Valence electrons…