The correct statement about ionization potential (IP) is:

Explanation:
- The ionization potential (IP) is defined as the amount of energy required to remove an electron from a gaseous atom or ion in its ground state.
- It is an important property of an atom as it determines the ease with which an atom can lose an electron and form a positive ion.
- The ionization potential is influenced by several factors, including the atomic size, electron-electron repulsion, and shielding effect.

Ionization potential and non-metallic character:
- The statement "Non-metallic character of an element decreases as the IP increases" is incorrect.
- Non-metallic character refers to the tendency of an element to gain electrons and form negative ions.
- Higher ionization potential indicates that it is more difficult to remove an electron from an atom or ion.
- Non-metallic elements generally have higher ionization potentials because they have strong attractions for their valence electrons.
- Therefore, non-metallic character increases as ionization potential increases.

Ionization potential and periodic trends:
- The ionization potential generally follows specific trends across the periodic table.
- As we move down a group in the periodic table, the ionization potential generally decreases.
- This is because the atomic size increases down a group, resulting in weaker attractions between the nucleus and the valence electrons.
- The increased atomic size also leads to increased electron shielding, reducing the effective nuclear charge experienced by the valence electrons.
- As a result, the valence electrons are more easily removed, leading to a decrease in ionization potential.

Comparison of ionization potentials:
- The statement "Second IP of Ca is larger than the second IP of K" is incorrect.
- The second ionization potential refers to the energy required to remove a second electron from a singly charged ion.
- The second ionization potential is generally higher than the first ionization potential as it becomes more difficult to remove an electron from a positively charged ion.
- However, the specific values of the ionization potentials depend on the elements involved.
- In the case of calcium (Ca) and potassium (K), the second ionization potential of Ca is lower than the second ionization potential of K.
- This is because calcium has a larger atomic size and higher electron shielding, making it easier to remove a second electron compared to potassium.

Ionization potential and left to right trend:
- The statement "IP decreases on going from left to right in the periodic table" is incorrect.
- As we move from left to right across a period in the periodic table, the ionization potential generally increases.
- This is due to the decrease in atomic size and the increase in effective nuclear charge.
- The valence electrons experience stronger attractions from the increasing positive charge of the nucleus, making them more difficult to remove.
- Therefore, the ionization potential generally increases from left to right in the periodic table.

In summary:
- The correct statement about ionization potential is that it decreases down the group in the periodic table.
- Non-metallic character increases as ionization potential increases.
- The second ionization potential of Ca is lower than the second ionization potential of K.
- The ionization potential generally increases from left to right in the periodic table.