Chemical Bonding — Practice Quiz

2 electrons

Step 1: Each chlorine atom has electronic configuration 2,8,7, meaning it has 7 electrons in its outer shell. Step 2: Each chlorine atom needs 1 more electron to complete its octet (8 electrons). Step 3: When two chlorine atoms come together, each contributes 1 electron for sharing. Step 4: This creates one shared pair of electrons (2 electrons total) between the two atoms. Step 5: Both chlorine atoms can now count these 2 shared electrons as part of their outer shell, giving each atom 8 electrons and completing their octets.

2,8,8

Step 1: A neutral chlorine atom has atomic number 17, so it has 17 electrons with configuration 2,8,7. Step 2: To form a chloride ion (Cl⁻), the chlorine atom gains one electron. Step 3: This additional electron goes into the outermost shell, making it 2,8,8. Step 4: The chloride ion now has 18 electrons but still has 17 protons, giving it a -1 charge. Step 5: The configuration 2,8,8 is the same as argon (a noble gas), making the chloride ion very stable.

They have weak intermolecular forces between molecules

Step 1: Covalent compounds exist as discrete molecules held together by sharing electrons within the molecule. Step 2: The forces between different molecules (intermolecular forces) are much weaker than the ionic forces in ionic compounds. Step 3: To melt a covalent compound, you only need to overcome these weak intermolecular forces, not break the strong covalent bonds within molecules. Step 4: In contrast, melting ionic compounds requires breaking strong electrostatic attractions between ions. Step 5: Since less energy is needed to overcome weak intermolecular forces, covalent compounds melt

3 bonds

Step 1: Each nitrogen atom has electronic configuration 2,5, meaning it has 5 electrons in its outer shell. Step 2: Each nitrogen atom needs 3 more electrons to complete its octet (8 electrons). Step 3: When two nitrogen atoms bond, each contributes 3 electrons for sharing. Step 4: This creates 3 shared pairs of electrons (6 electrons total) between the two atoms. Step 5: These 3 pairs of shared electrons form 3 covalent bonds, creating a triple bond (N≡N), which is very strong.