A covalent bond forms when
(1)two nuclei share electrons in order to achieve a complete octet of electrons
(2) atoms form ions and then electrostatic forces of attraction bond the ions together.
(3)repulsive forces between atoms are greater than the attractive forces
(4) a metal atom combines with a nonmetal atom
please help !
Actually, none of the choices is correct. I think, however, it was intended for #1 to be the answer. That statement is true for elements except for the H2 molecules(share two electrons) and a few others like NO2.
A covalent bond forms when option 1 is true: two nuclei share electrons in order to achieve a complete octet of electrons.
The correct answer is (1) two nuclei share electrons in order to achieve a complete octet of electrons.
To determine the answer, you need to understand the concept of covalent bonding.
A covalent bond is formed between two nonmetal atoms when they share electrons. This type of bond occurs most commonly between atoms that are close to achieving a stable electron configuration known as an octet, which consists of eight valence electrons in the outermost energy level.
In a covalent bond, each atom contributes one or more electrons to the shared electron pair, resulting in the formation of a molecule. The shared electrons are located in the overlapping region between the atomic orbitals of the two bonding atoms. By sharing electrons, both atoms can achieve a more stable electron configuration and increase their chances of achieving a complete octet, similar to the noble gases.
Option (1) describes this process accurately, as two nuclei (the positive cores of the atoms) share electrons to achieve a complete octet of electrons. In contrast, option (2) describes the formation of ionic bonds, where atoms transfer electrons to form oppositely charged ions that are then attracted to each other by electrostatic forces. Option (3) is incorrect because covalent bonds generally occur due to attractive forces between shared electrons and the nuclei of atoms, rather than repulsive forces. Option (4) refers to the formation of ionic compounds, not covalent bonds.
Therefore, the correct answer is (1) two nuclei share electrons in order to achieve a complete octet of electrons.