Given the following compounds: H2, HBr, HCl, HF
A. Which will form an ionic bond?
B. Which will form a nonpooar covalent bond?
C. Which will form a polar covalent bond?
A. HBr and HCl
B, H2
C. HF
BUT you REALLY need to understand why.
None will form ionic bonds as a metal + nonmetal are required to generate the ionic compound. HF, HCl & HBr are polar covalent molecules with HF having the higher polarity followed by HCl and lastly HBr. However, it's interesting to note that (if in aqueous medium) the trend in acidity for this set of acids finds the HBr as the stronger acid followed by HCl, then HF as the weakest of the three. HF is actually a weak acid (Ka = 6.6E-4) in this set whereas HCl and HBr are strong acids (Ka = Infinity => 100% ionized). The reason is 'ionic radii' govern the ionization potential for the groups periodic trend and not electronegativity which is a series periodic trend. This, FYI, is known as the 'Hydrogen-Halide Paradox'. Hâ‚‚(g) is the lone non-polar covalent structure.
Certainly it is true that gaseous HCl and gaseous HBr are polar covalent; however, aqueous solution of both are ionic.
Identify which of the following compound are formed by covalent bonds
1.HBr
2.CCl4
3.CH4
Convalent bond
To determine which compounds will form an ionic bond, nonpolar covalent bond, and polar covalent bond, you need to consider the difference in electronegativity between the atoms involved in the bond.
Electronegativity is a measure of an atom's ability to attract electrons towards itself in a chemical bond. When the electronegativity difference is large between two atoms, they tend to form an ionic bond. When the electronegativity difference is small, they form a covalent bond, which can be either nonpolar or polar depending on the nature of the atoms involved.
Let's now determine which compounds fall into each category:
A. Ionic bond:
An ionic bond forms when there is a large electronegativity difference between the atoms. In this case, H2 does not form an ionic bond because hydrogen (H) has a lower electronegativity than most other elements. Therefore, none of the given compounds will form an ionic bond.
B. Nonpolar covalent bond:
A nonpolar covalent bond forms when there is little to no electronegativity difference between the atoms involved. This means that the atoms in the bond have similar electronegativities, and the electrons are shared equally. H2 is an example of a nonpolar covalent bond because hydrogen (H) has a similar electronegativity value. Therefore, H2 will form a nonpolar covalent bond.
C. Polar covalent bond:
A polar covalent bond forms when there is a moderate electronegativity difference between the two atoms involved. Electrons in a polar covalent bond are not shared equally, creating partial positive and partial negative charges within the molecule. Out of the remaining compounds, HBr, HCl, and HF, the one with the greatest electronegativity difference is HF. Fluorine (F) is the most electronegative element among these choices, causing the bond to be polar. Thus, HF will form a polar covalent bond.
To summarize:
A. None of the compounds will form an ionic bond.
B. H2 will form a nonpolar covalent bond.
C. HF will form a polar covalent bond.