Answer: K only has 1 valence electron. It will leave with only a little effort, leaving behind a positively charged K^+1 atom.
Explanation: A neutral potassium atom has 19 total electrons. But only 1 of them is in potassium's valence shell. Valence shell means the outermost s and p orbitals. Potasium's electron configuration is 1s^2 2s^2 2p^6 3s^2 3p^6 4s^1. The 4s orbital is the only orbital in the 4th energy level. So it has a valency of 1. This means this electron will be the most likely to leave, since it is the lone electron in the oyutermost energy level (4). When that electron leaves, the charge on the atom go up by 1. The atom now has a full valence shell of 3s^2 3p^6, the same as argon, Ar.
Answer: because it consists of more than one element, which are hydrogen and oxygen in a covalent bond.
Explanation:
Atomic number is defined as the number of an element which represents total number of protons.
When an atom is neutral then it means it contains same number of protons and electrons.
On the other hand, atomic mass is defined as the sum of total number of protons and neutrons present in an atom.
Protons of every element remains fixed because it shows the identity of each element but if we change the number of neutrons then also identity of the atom will remain fixed. This is because changing the number of neutrons will not show any change in number of protons.
For example, 
and 
are isotopes of hydrogen and they have same number of protons but different number of neutrons.
Thus, we can conclude that number of neutrons can vary without changing the identity of the element.
Answer:
D
Explanation:
Mendeleev periodic table predicted the properties of undiscovered element like the eka-aluminium.
The products of reaction are ZnSO4 and H2. Since ZnSO4 is in aqueous form (aq), therefore only H2 and water vapor contributes to the overall total pressure in the system.
Total Pressure = 764 torr = H2 partial pressure + Water partial pressure
Since Water partial pressure is 26.74 torr so,
H2 partial pressure = 737.26 torr = 0.97 atm
