List I | List II | ||
---|---|---|---|
A | Two or more alternative forms of a gene | I | Back cross |
B | Cross of F1 progeny with homozygous recessive parent | II | Ploidy |
C | Cross of F progeny with any of the parents | III | Allele |
D | Number of chromosome sets in plant | IV | Test cross |
List I (Sub Phases of Prophase I) | List II (Specific characters) | ||
A | Diakinesis | I | Synaptonemal complex formation |
B | Pachytene | II | Completion of terminalisation of chiasmata |
C | Zygotene | III | Chromosomes look like thin threads |
D | Leptotene | IV | Appearance of recombination nodules |
List-I | List-II | ||
(A) | mI | (I) | Shape of orbital |
(B) | ms | (II) | Size of orbital |
(C) | I | (III) | Orientation of orbital |
(D) | n | (IV) | Orientation of spin of electron |
The atomic structure of an element refers to the constitution of its nucleus and the arrangement of the electrons around it. Primarily, the atomic structure of matter is made up of protons, electrons and neutrons.
Dalton proposed that every matter is composed of atoms that are indivisible and indestructible.
The following are the postulates of his theory:
Several atomic structures of an element can exist, which differ in the total number of nucleons.These variants of elements having a different nucleon number (also known as the mass number) are called isotopes of the element. Therefore, the isotopes of an element have the same number of protons but differ in the number of neutrons. For example, there exist three known naturally occurring isotopes of hydrogen, namely, protium, deuterium, and tritium.