The first use of quantum theory to explain the structure of atom was made by –
Plum-Pulding model is known as–
Thomson proposed the plum pudding model of the atom, which had negatively-charged electrons embedded within a positively-charged "soup." Rutherford's gold foil experiment showed that the atom is mostly empty space with a tiny, dense, positively-charged nucleus.
Nucleous consist of–
The number of valence electron in Na is –
Mass number of element is –
According to the Dalton's atomic theory –
Neutron is a fundamental particle which have–
No. of unpaired electron in 1s2.2s2.2p4
Hund's rule says , when electrons are filled in orbitals of equal energy, one electron enters each orbital until all the orbitals contain one electron with the same spin direction. Then the pairing of electrons take place.
Thus in electronic configuration, the electrons in p subshell are filled in 3 orbitals such that every orbital contains one electron each. The fourth electron will be paired up with the first electron and the other two electrons remain unpaired.
The electron should be filled in the orbital in accordance with the increasing order of their energy. This statement
is related with
This statement is related with Aufbau principle.
According to Aufbau principle (also known as (n+l) rule), electrons are filled in different orbitals from lower (n+l) value orbital to higher (n+l) value orbital.
In case (n+l) value is same, electron is filled first in orbital with lower value of n.
Which species does not contain neutron –
In an atom, the mass number of an atom is equal to the number of___________.
Atomic number of any element–
Lighest particle is –
Fundamental particle of atomic nucleus is–
The atomic size of atom is nearly –
An atom which has a mass number of 14 or 8 neutrons is–
Isotopes are the atoms of the same element with similar atomic number but different atomic mass.The elements of isotopes share same chemical properties but different physical properties
Electronic configuration of p in ground state is –
When a gas at reduced pressure is subjected to an electric discharge, the rays orignating from the negative electrode are–
Cathode ray, stream of electrons leaving the negative electrode (cathode) in a discharge tube containing a gas at low pressure, or electrons emitted by a heated filament in certain electron tubes. Cathode rays focused on a hard target (anticathode) produce X-rays or focused on a small object in a vacuum generate very high temperatures (cathode-ray furnace). When cathode rays strike certain molecules used to coat a cathode screen, they cause the molecules (and hence the screen) to emit light.
The maximum number of electrons that can be accomodate in the nth level is–
Isotopes of an element are the atom which have –
The nucleus of an atom contains:
What is the no. of electrons in Argon?
The no. of electrons is the atomic number of an element.
The isotope deuterium of hydrogen has
The no. of electrons in the valence shells of Sodium and Calcium repectively:
Electronic configuration of
Na is 2, 8, 1
Ca is 2, 8, 8, 2
The maximum number of electrons that can be accommodated in third shell ( n = 3) is: