Chemistry
Which statement is incorrect about electrons ?
- Electron is a negatively charged particle.
- Its mass is equal to the mass of neutron.
- It is a constituent of cathode rays.
- It is a basic constituent of all atoms.
Answer
Its mass is equal to the mass of neutron.
Reason - The electron is extremely light compared to a neutron.
Electrons are negatively charged. Cathode rays are streams of electrons. Electrons are fundamental components of all atoms.
Cathode rays are streams of electrons emitted from the cathode in a vacuum tube. This was one of the key discoveries proving the existence of electrons. Electrons are found in all atoms (except hydrogen ion H⁺, which has lost its electron). They occupy the space around the nucleus and are responsible for chemical bonding and reactions.
Related Questions
An element Y has 2 electrons in the 2nd orbit and X has 7 electrons in its 3rd orbit. The compound formed between them has the formula:
- XY2
- YX2
- YX
- Y7X2
Which of the following statements is not correct about the characteristics of cathode rays ?
- They start from cathode and move towards anode.
- They do not depend upon the material of the electrode.
- Their characteristics depend upon the nature of the gas present in the cathode ray tube.
- They travel in straight lines in the absence of an external electrical or magnetic fields.
Two atoms are said to be isobars if they have the same:
- number of neutrons but different number of electrons.
- number of electrons but different number of neutrons.
- atomic number but different mass numbers.
- sum of protons and neutrons but the number of protons is different.
An atom is neutral, its nucleus contains:
P — Negatively charged particles.
Q — Neutral particles.
R — Positively charged particles.
- Only P
- Only Q
- Only R
- Both Q and R