Structure of the atom short 1 and read the textbook Flashcards
Who discovered the electron ?
JJ Thompson and said the mass of an electron is considered to be negligible and its charge is minus one
Who discovered Canal rays ?
E. Goldstein
What are Canal rays ?
These rays were positively charged radiations which led to the discovery of another sub-atomic particle.
What are the postulates of Neils Bohr
(i) Only certain special orbits known as discrete orbits of electrons, are allowed inside the atom.
(ii) While revolving in discrete orbits the electrons do not radiate energy.
The distribution of electrons into different
orbits of an atom was suggested by_______________.
Bohr and Bury
What are valance electrons
The electrons present in the outermost shell of an atom
What are protons and neutrons also called ?
Nucleons
What is the mass number
The mass number is defined as the sum of the total number of protons and neutrons present in the nucleus of an atom. It is denoted by ‘A’
What are the uses of isotopes ?
(i) An isotope of uranium is used as a fuel in nuclear reactors.
(ii) An isotope of cobalt is used in the treatment of cancer.
(iii) An isotope of iodine is used in the treatment of goitre.
What are isobars
Atoms of different elements with different atomic numbers which have the same mass number are known as isobars.
