Question

How does the ionization energy change at the start of each new period of elements

Answer 1

Ответ:

Moving left to right within a period or upward within a group, the first ionization energy generally increases. As the atomic radius decreases, it becomes harder to remove an electron that is closer to a more positively charged nucleus. ... They experience a weaker attraction to the positive charge of the nucleus.

Answer 2

The ionization energy generally increases as you move from left to right across a period (horizontal row) of the periodic table. This is due to the following factors:

1. Effective Nuclear Charge: As you move across a period from left to right, the number of protons in the nucleus increases. This leads to a stronger positive charge in the nucleus, pulling the negatively charged electrons closer to it. This increased effective nuclear charge requires more energy to remove an electron, resulting in higher ionization energy.

2. Atomic Size: As you move across a period, the atomic size generally decreases. This is because the increasing number of protons in the nucleus pulls the electrons closer to the nucleus, resulting in a stronger attractive force. With electrons held more tightly, it becomes more difficult to remove an electron, thus requiring more energy to do so.

3. Shielding Effect: Although electrons are negatively charged, they also repel each other due to their like charges. The inner electrons (closer to the nucleus) shield the outer electrons from the full effect of the nuclear charge. As you move across a period, the number of inner electrons remains relatively constant, so the shielding effect doesn't increase significantly. This means the increase in effective nuclear charge plays a more dominant role in the ionization energy trend.

It's important to note that there can be some exceptions and variations due to specific electron configurations and elements transitioning between different blocks (s, p, d, f) in the periodic table. For example, the ionization energy of transition metals may not increase uniformly across a period due to the filling of d orbitals.

In summary, the ionization energy generally increases at the start of each new period of elements due to the combination of increased effective nuclear charge and smaller atomic size.