Na and Cl does not form covalent bond because:
The correct option is A higher electronegativity difference (2.1)
Sodium (Na), for example, has one electron in its valence
shell. This is an unstable state because that valence shell needs eight
electrons to be full. Atoms like sodium, with only one or two electrons in a
valence shell that needs eight electrons, are most likely to give up their
valence electrons to achieve a stable state. All these atoms need is another
atom that can attract their electrons!
An atom such as chlorine (Cl), that contains seven electrons
in its valence shell, needs one more electron to have a full valence shell. If
we use the same logic as we did for sodium, we should conclude that chlorine
would rather gain one more electron than lose all seven of its valence
electrons to achieve stability. Under the right conditions, atoms like chlorine
will steal an electron from nearby atoms like sodium. This ability to pull
electrons away from other atoms is termed electronegativity. Atoms with a
valence shell that is almost full are more likely to be electronegative because
they have greater reason to pull electrons towards them. Electronegative atoms
are not negatively charged, but they are more likely to become negatively
charged.
Sodium (Na), for example, has one electron in its valence shell. This is an unstable state because that valence shell needs eight electrons to be full. Atoms like sodium, with only one or two electrons in a valence shell that needs eight electrons, are most likely to give up their valence electrons to achieve a stable state. All these atoms need is another atom that can attract their electrons!
An atom such as chlorine (Cl), that contains seven electrons in its valence shell, needs one more electron to have a full valence shell. If we use the same logic as we did for sodium, we should conclude that chlorine would rather gain one more electron than lose all seven of its valence electrons to achieve stability. Under the right conditions, atoms like chlorine will steal an electron from nearby atoms like sodium. This ability to pull electrons away from other atoms is termed electronegativity. Atoms with a valence shell that is almost full are more likely to be electronegative because they have greater reason to pull electrons towards them. Electronegative atoms are not negatively charged, but they are more likely to become negatively charged.
