What is the electron arrangement around an atom in a molecule or ion which is surrounded by three lone pairs of electrons and one single bond

Tetrahedral

Explanation:

According to the valence shell electron pair repulsion theory, the number of electron pairs on a molecule determines the arrangement of electrons around the central atom of the molecule or ion.

In this case, there are four electron pairs around the central atom in the molecule or ion hence they are arranged in tetrahedral geometry. Note that the lone pairs only determine the molecular geometry and  not the electron geometry or arrangement.

answer

fusion: the energy source of stars. the energy released from the collapse of the gas into a protostar causes the center of the protostar to become extremely hot. when the core is hot enough, nuclear fusion commences. fusion is the process where two hydrogen atoms combine to form a helium atom, releasing energy.

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