I think it will be D or B but my mine answer is D
Answer:
Nuclear fusion plays an important role in making elements that are heavier than helium.
Explanation:
Nucleosynthesis is the process by which new atomic nuclei are created from pre-existing nucleons (protons and neutrons) and nuclei. According to current theories, the first nuclei were formed a few minutes after the Big Bang, through nuclear reactions in a process called Big Bang nucleosynthesis.
In order to synthesize a new element, there must be a change in the number of protons. We should remember that elements are known by the number of their protons as it represents their atomic number.
Elements heavier than helium are formed by nuclear nucleosynthesis in which nuclear fusion plays a very crucial role as typified by the equations shown in the question.
Answer:
AS we move from bottom to top on periodic table shielding decreased.
Explanation:
As we move from left to right across the periodic table the number of valance electrons in an atom increase. The atomic size tend to decrease in same period of periodic table because the electrons are added with in the same shell. When the electron are added, at the same time protons are also added in the nucleus. The positive charge is going to increase and this charge is greater in effect than the charge of electrons. This effect lead to the greater nuclear attraction.
As we move down the group atomic radii increased with increase of atomic number. The addition of electron in next level cause the atomic radii to increased. The hold of nucleus on valance shell become weaker because of shielding of electrons thus size of atom increased.
As we move from bottom to top the energy level decreased because of decreased in electron thus shielding decreased and atomic size also decreased.
Answer:
Axial
Explanation:
In the most stable conformation of Cis-3-tert-Butylcyclohexanol, the tert-butyl group is at equatorial position and the alcohol group is in the axial position.
If the tert-butyl group is placed in equatorial position, repulsions are minimized. The bulkier the group, the greater the energy difference between the axial and equatorial conformers. Hence for a ring having a bulky substituent, such bulky substituent is better placed in the equatorial position.
The energy difference between the conformers of Cis-3-tert-Butylcyclohexanol is so high that the compound is almost "frozen" in a conformation where the tert-butyl groups are equatorial and the -OH groups are axial. This conformer is more stable by 24 KJ/mol.
