Why is the atomic radius of Boron smaller than that of Be?

In summary, the 1st ionization energy decreases from Be to B, indicating a looser hold on the outermost electron in B. Despite having an extra p orbital, the atomic radius of B is smaller than that of Be due to the higher nucleus charge in B. Additionally, the non-spherical shape of the p-state and the collective electronic effect may also contribute to the smaller atomic radius of B."
  • #1
mahela007
106
0
The 1st ionization energy decreases from Be to B. This would suggest that the outermost electron is held more loosely in B. Also, considering the electron configurations of Be (1s2 2s2) and B (1s2 2s2 2p1) one would think that in B, the shielding effect of the 2s electrons on the p electron would also act to increase the atomic radius...
but alas :wink: that isn't how it is... Now.. the universal question: WHY?
 
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  • #2
Because the configuration (1s2 2s2) in B is smaller in size due to higher nucleus charge, no?
 
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  • #3
Wait.. i think I made a mistake in my initial post.
What I meant to ask was why is the atomic radius of B smaller when it has an extra P orbital which is also shielded by full 1s and 2s orbitals?
 
  • #4
mahela007 said:
Wait.. i think I made a mistake in my initial post.
What I meant to ask was why is the atomic radius of B smaller when it has an extra P orbital which is also shielded by full 1s and 2s orbitals?

Ion B+ radius is smaller than that of neutral Be despite the same electron configuration 1s2 2s2 just because the charge of nucleus in B is higher. The rest is a collective electronic effect, I think.

Besides, a p-state is not spherical. Which axe (dimension) is considered as the B-size?
 
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FAQ: Why is the atomic radius of Boron smaller than that of Be?

1. Why is the atomic radius of Boron smaller than that of Be?

The atomic radius of an element is determined by the number of protons and electrons in its nucleus. Boron has 5 protons and 5 electrons, while Be has 4 protons and 4 electrons. This means that Boron has a higher nuclear charge, pulling its electrons closer to the nucleus and resulting in a smaller atomic radius compared to Be.

2. How does the number of valence electrons affect the atomic radius of an element?

The number of valence electrons plays a significant role in determining the atomic radius of an element. As the number of valence electrons increases, the atomic radius also increases. This is because the outermost electrons are located farther from the nucleus and experience less attraction, resulting in a larger atomic radius.

3. Why does the atomic radius decrease as you move across a period on the periodic table?

As you move across a period on the periodic table, the number of protons and electrons in the nucleus increases. This increases the nuclear charge, pulling the electrons closer to the nucleus and making the atomic radius smaller. Additionally, as you move across a period, the number of energy levels remains the same, causing the electrons to be more tightly packed and decreasing the atomic radius.

4. How does the atomic radius of Boron compare to that of other elements in its group?

Boron belongs to Group 13 on the periodic table, also known as the Boron group. In this group, the atomic radius decreases as you move down the group. This is because as you move down the group, the number of energy levels increases, causing the outermost electrons to be located farther from the nucleus and resulting in a larger atomic radius. Thus, the atomic radius of Boron is smaller than that of other elements in its group.

5. Does the atomic radius of an element affect its chemical properties?

Yes, the atomic radius of an element can significantly impact its chemical properties. Elements with smaller atomic radii tend to have stronger attraction between their protons and electrons, making them more reactive and likely to form chemical bonds. On the other hand, elements with larger atomic radii have weaker attraction and are less reactive. This is due to the fact that larger atoms have more energy levels, making it easier for them to lose or gain electrons to achieve a stable configuration.

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