Explanation:
<h3>Atomic Number and Mass</h3>
Each element has its own unique properties. Each contains a different number of protons and neutrons, giving it its own atomic number and mass number. The atomic number of an element is equal to the number of protons that element contains.
Answer:
K
Explanation:
Ionization energy refers to the energy required to remove an electron from an atom. It usually increases across the period due to the increase in the size of the nuclear charge and decreases down the group due to increase in the number of shells.
If we look at the element, K, it has only one electron in its outermost shell. This implies that after this one electron is removed, the second ionization energy involves the removal of an electron from a filled shell.
This usually requires a lot of energy. Hence, the element having the highest difference in energy between first and second ionization energy is K.
Answer:
Chemical science arises in the seventeenth century from the studies of alchemy popular among many of the scientists of the time. The basic principles of chemistry are considered to be collected for the first time in the work of the British scientist Robert Boyle: The Skeptical Chemist (1661).
The internal energy has the symbol U. Q is positive if heat is added to the system, and negative if heat is removed;
....."W is positive if work is done by the system"........
and negative if work is done on the system.
So, work done by a system is positive.
