Advertisements
Advertisements
प्रश्न
State the main postulates of Dalton’s atomic theory.
Advertisements
उत्तर
- Matter consists of small indivisible particles called atoms, i.e., an atom is the basic unit of matter.
- Atoms of the same element are alike in all respects, i.e., atoms of hydrogen have the same properties, such as mass and density, and atoms of oxygen are alike in all respects.
- Atoms of different elements are different from each other. i.e., atoms of hydrogen are different from atoms of oxygen.
- An atom can neither be created nor destroyed.
- Atoms combine with other atoms in a simple whole-number ratio, forming compounds or molecules.
APPEARS IN
संबंधित प्रश्न
What are the atomic numbers of elements whose outermost electrons is represented by 2p3.
In Milikan’s experiment, static electric charge on the oil drops has been obtained by shining X-rays. If the static electric charge on the oil drop is - 1.282 × 10-18C, calculate the number of electrons present on it.
Write true or false for the following statement
An atom on the whole has a positive charge.
Multiple Choice Questions
If the atomic number of an atom is 17 and mass number is 35 then number of neutron will be
Fill in the following blanks in respect of an atom of an element
| No. of protons | No. of neutron | Mass number | Atomic number | No. of electrons | Symbol |
| 11 | 12 | ___________ | ___________ | ___________ | ________ |
(a) What is meant by (i) atomic number, and (ii) mass number, of an element? Explain with the help of an example.
(b) What is the relation between the atomic number and mass number of an element?
(c) If an element M has mass number 24 and atomic number 12, how many neutrons does its atom contain?
Match the atomic numbers 4,8,10,15 and 19 with the following:
Element with four shells
Draw the atomic diagram of the following element showing the distribution of – protons, neutrons and the electrons in the various shell of the atom.
Carbon – \[\ce{^12_6C}\]
[The upper number represent the – mass number and the lower number represent the – atomic number e.g. calcium – mass number = 40, atomic number = 20]
Draw the atomic diagram of the following element showing the distribution of – protons, neutrons and the electrons in the various shell of the atom.
Phosphorus – \[\ce{^31_15P}\]
[The upper number represent the – mass number and the lower number represent the – atomic number e.g. calcium – mass number = 40, atomic number = 20]
Electrons revolve around the nucleus in definite open shells.
