Problem: How many lone pairs are on the central atom in BCl3?Express your answer numerically as an integer.Hydrogen, beryllium, and boron are examples of elements that can have less than an octet of electrons in a covalent compound. Even without an octet, hydrogen achieves the helium configuration, and therefore noble-gas stability, by forming one covalent bond. Beryllium and boron simply do not have enough electrons to form the number of bonds needed to achieve an octet. Instead, Be uses its two valence electrons to form two bonds, and B uses its three valence electrons to form three bonds. None of these elements will have any lone pairs.Elements in the third row of the periodic table and beyond can have more than an octet of electrons in a covalent compound. This can be explained by the existence of an empty d subshell available to these elements, which allows them to expand their valence to a number greater than eight.

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How many lone pairs are on the central atom in BCl3?

Express your answer numerically as an integer.


Hydrogen, beryllium, and boron are examples of elements that can have less than an octet of electrons in a covalent compound. Even without an octet, hydrogen achieves the helium configuration, and therefore noble-gas stability, by forming one covalent bond. Beryllium and boron simply do not have enough electrons to form the number of bonds needed to achieve an octet. Instead, Be uses its two valence electrons to form two bonds, and B uses its three valence electrons to form three bonds. None of these elements will have any lone pairs.

Elements in the third row of the periodic table and beyond can have more than an octet of electrons in a covalent compound. This can be explained by the existence of an empty d subshell available to these elements, which allows them to expand their valence to a number greater than eight.

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What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Lewis Dot Structure concept. You can view video lessons to learn Lewis Dot Structure. Or if you need more Lewis Dot Structure practice, you can also practice Lewis Dot Structure practice problems.