Question

1 multiple choice 1 point which factor primarily determines whether a bond is polar? the difference in electronegativity between bonded atoms the number of protons in each atom. the number of neutrons in each atom the total mass of the molecule 2 multiple choice 1 point how does atomic radius generally affect bond polarity? larger atoms have valence electrons farther from the nucleus, which can reduce bond strength and affect polarity larger atoms pull electrons more strongly, increasing polarity atomic radius does not affect polarity smaller atoms pull electrons less strongly, decreasing polarity 3 multiple choice 1 point which of the following molecules is nonpolar? hcl nh₃ h₂o co₂

Explanation:

• Question 1: A polar bond is formed when there is a significant difference in electronegativity between the bonded atoms. Electronegativity is the ability of an atom to attract electrons in a chemical bond. If two atoms have a large difference in electronegativity, the electrons will be more strongly attracted to the more electronegative atom, creating a dipole moment (a separation of charge) and a polar bond. The number of protons affects the atomic number and some properties like ionization energy but not directly bond polarity. Neutrons are neutral and do not affect the electron - sharing in a bond. The total mass of the molecule is related to physical properties like density and boiling point, not bond polarity.
• Question 2: Larger atoms have their valence electrons farther from the nucleus. The effective nuclear charge (the net positive charge experienced by the valence electrons) is reduced for these outer - shell electrons. As a result, the ability of the atom to attract electrons (electronegativity) is reduced. This can reduce the bond strength (since the electron - sharing is less strong) and affect polarity. Larger atoms do not pull electrons more strongly (as their valence electrons are farther from the nucleus, the attraction is weaker). Atomic radius does affect polarity as explained. Smaller atoms have a higher effective nuclear charge for their valence electrons (since the electrons are closer to the nucleus) and pull electrons more strongly.
• Question 3:
• For \(HCl\), hydrogen (\(H\)) has an electronegativity of approximately \(2.1\) and chlorine (\(Cl\)) has an electronegativity of approximately \(3.0\). There is a significant electronegativity difference (\(\Delta\chi=3.0 - 2.1=0.9\)), so \(HCl\) is polar.
• For \(NH_3\) (ammonia), the \(N - H\) bonds are polar (electronegativity of \(N = 3.0\) and \(H=2.1\)). Also, the molecular geometry is trigonal pyramidal, which means the dipole moments do not cancel out, and \(NH_3\) is polar.
• For \(H_2O\) (water), the \(O - H\) bonds are polar (\(O\) has an electronegativity of \(3.5\) and \(H = 2.1\)). The bent molecular geometry results in non - canceling dipole moments, so \(H_2O\) is polar.
• For \(CO_2\) (carbon dioxide), the \(C - O\) bonds are polar (\(C\) has an electronegativity of \(2.5\) and \(O = 3.5\)). But the molecular geometry is linear (\(O = C=O\)). The dipole moments of the two \(C - O\) bonds are equal in magnitude and opposite in direction, so they cancel each other out, making \(CO_2\) non - polar.

Answer:

1. The difference in electronegativity between bonded atoms
2. Larger atoms have valence electrons farther from the nucleus, which can reduce bond strength and affect polarity
3. \(CO_2\)