Simply look at the periodic table and fill in what you know based on the table
The number of protons = atomic number
The number of electrons, Which is the same as the atomic number for atoms.
The number of valence electrons that is given by the group that the element is in, the top number of each column in the periodic table.
Answer: 250 kJ
Explanation: According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.
According to Hess’s law, the chemical equation can be treated as algebraic expressions and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.
(1)
(2)
Net chemical equation:
(3)
Adding 1 and 2 we get,
(4)
Now dividing equation (4) by 4, we get
(4)
Oxygen has 8 electrons. On the outer ring, it has 6 valance electrons. It need 2 more valance electrons to be stable.
Neptune planet has the coldest surface temperature
<u>Explanation:</u>
With temperatures falling to -218°C in Neptune’s upper atmosphere, the planet is one of the coolest in our Solar System. Neptune is the most faraway planet from the sun. Astronomers have speculated that Neptune's huge internal temperature and the transfer of heat between the core and outer layers might be the cause why Neptune isn't significantly more chill than Uranus.
Pressures in this area range between 1 and 5 bars and the temperature reaches a high of 72 K. At this temperature, states are becoming for methane to condense, and clouds of ammonia and hydrogen sulfide are thought to form. At its core, Neptune reaches temperatures of up to 7273 K which is equivalent to the surface of the sun.
The answer would be A. Genotype
