Answer :
To determine which atom will have the lowest ionization energy, we need to understand the concept of ionization energy and trends in the periodic table.
### Ionization Energy:
Ionization energy is the energy required to remove an electron from an atom in the gaseous state. Higher ionization energy means it is more difficult to remove an electron.
### Trends in the Periodic Table:
1. Across a Period (Left to Right):
- Ionization energy generally increases as you move from left to right across a period. This is because the effective nuclear charge increases, causing the electrons to be more strongly attracted to the nucleus.
2. Down a Group (Top to Bottom):
- Ionization energy generally decreases as you move down a group. This is because the electrons are farther from the nucleus and are more shielded by inner electrons, so they are less strongly attracted to the nucleus.
Let's consider the elements mentioned:
- N (Nitrogen):
- Located in Group 15, Period 2
- Atomic number: 7
- H (Hydrogen):
- Located in Group 1, Period 1
- Atomic number: 1
- C (Carbon):
- Located in Group 14, Period 2
- Atomic number: 6
- Si (Silicon):
- Located in Group 14, Period 3
- Atomic number: 14
### Comparing the Elements:
1. Nitrogen (N) vs. Hydrogen (H):
- N is further to the right than H, and H is at the top of the periodic table.
- N has higher ionization energy than H because it is further across the period and thereby has higher effective nuclear charge.
2. Carbon (C) vs. Hydrogen (H):
- C is to the right of H and below N.
- C has higher ionization energy than H since it is further across the period though not as high as N.
3. Silicon (Si) vs. Hydrogen (H):
- Si is below C in Group 14.
- Si has lower ionization energy than C because it is further down the group, so Si has more shielding and electrons are less tightly bound.
4. Carbon (C) vs. Nitrogen (N):
- N is to the right of C.
- N has higher ionization energy than C as one moves right across the period.
5. Silicon (Si) vs. Carbon (C):
- Si is below C in the same group.
- Si has lower ionization energy than C as you move down the group.
From these comparisons, we see that:
- Hydrogen has lower ionization energy than Carbon and Nitrogen.
- Silicon has lower ionization energy than Carbon because it is below Carbon in the same group.
Between Hydrogen and Silicon, Silicon will have the lower ionization energy because it is further down in Group 14 compared to Hydrogen being in Group 1 but with only one electron very close to the nucleus.
### Conclusion:
The atom with the lowest ionization energy among N, H, C, and Si is Silicon (Si).
### Ionization Energy:
Ionization energy is the energy required to remove an electron from an atom in the gaseous state. Higher ionization energy means it is more difficult to remove an electron.
### Trends in the Periodic Table:
1. Across a Period (Left to Right):
- Ionization energy generally increases as you move from left to right across a period. This is because the effective nuclear charge increases, causing the electrons to be more strongly attracted to the nucleus.
2. Down a Group (Top to Bottom):
- Ionization energy generally decreases as you move down a group. This is because the electrons are farther from the nucleus and are more shielded by inner electrons, so they are less strongly attracted to the nucleus.
Let's consider the elements mentioned:
- N (Nitrogen):
- Located in Group 15, Period 2
- Atomic number: 7
- H (Hydrogen):
- Located in Group 1, Period 1
- Atomic number: 1
- C (Carbon):
- Located in Group 14, Period 2
- Atomic number: 6
- Si (Silicon):
- Located in Group 14, Period 3
- Atomic number: 14
### Comparing the Elements:
1. Nitrogen (N) vs. Hydrogen (H):
- N is further to the right than H, and H is at the top of the periodic table.
- N has higher ionization energy than H because it is further across the period and thereby has higher effective nuclear charge.
2. Carbon (C) vs. Hydrogen (H):
- C is to the right of H and below N.
- C has higher ionization energy than H since it is further across the period though not as high as N.
3. Silicon (Si) vs. Hydrogen (H):
- Si is below C in Group 14.
- Si has lower ionization energy than C because it is further down the group, so Si has more shielding and electrons are less tightly bound.
4. Carbon (C) vs. Nitrogen (N):
- N is to the right of C.
- N has higher ionization energy than C as one moves right across the period.
5. Silicon (Si) vs. Carbon (C):
- Si is below C in the same group.
- Si has lower ionization energy than C as you move down the group.
From these comparisons, we see that:
- Hydrogen has lower ionization energy than Carbon and Nitrogen.
- Silicon has lower ionization energy than Carbon because it is below Carbon in the same group.
Between Hydrogen and Silicon, Silicon will have the lower ionization energy because it is further down in Group 14 compared to Hydrogen being in Group 1 but with only one electron very close to the nucleus.
### Conclusion:
The atom with the lowest ionization energy among N, H, C, and Si is Silicon (Si).
