Which one of the following bonds would be best categorized as covalent (molecular)? 1. H--S 2. S--O 3. N--F

1 only
1 and 2
1 and 3
1, 2 and 3

1, 2 and 3

Explanation:

A covalent bond, also called a molecular bond, is a chemical bond that involves the sharing of electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs, and the stable balance of attractive and repulsive forces between atoms, when they share electrons , is known as covalent bonding.

A covalent bond involves as stated above, the mutual sharing of one or more electron pairs of between two atoms. These electrons are simultaneously attracted by the two atomic nuclei. A covalent bond forms when the difference between the electronegativities of two atoms is too small for an electron transfer to occur to form ions. Shared electrons located in the space between the two nuclei are called bonding electrons. The bonded pair is the binding factor that holds the two atomic nuclei together in molecular units.

A covalent bond is commonly formed between two nonmetals. As we can see in the question; 1, 2 and 3 represents bonds formed between two nonmetallic elements. Hence they are rightly classified as molecular or covalent bonds.

at the bottom

explanation:

"among the transition metal elements, manganese and zinc have a slight lowering of electronegativities. the reason behind this is that the nuclear charges of these elements are slightly weaker than the other transition metal elements due to the way their valence electrons are filled up. both manganese and zinc have their valence electrons filled up to the 4th shell with 1 pair of electrons (4s2) completely occupying it. although the electrons in the 3rd shell (3d) are yet to be paired since the outer most shell is filled up, the ability of the nucleus to attract electrons is lessened. hence,   the electronegativity (or the ability to attract electrons) is lessened."