Question

1. what is the most stable group on the periodic table? why is this group stable?
2. name the most reactive group(s) on the periodic table? why are they reactive?
3. in the boxes below draw the electron dot diagrams for:

sodium
calcium
boron
chlorine
krypton

1. name the two (2) types of chemical bonds:
2. define ionic bond:
3. define covalent bond:
4. in an ionic bond, electrons are ______________
5. what type of elements participate in an ionic bond?
6. an ion with a positive charge is as a __________; an ion with a negative charge is an __________
7. in a covalent bond, electrons are ______________
8. what type of elements participate in a covalent bond?
9. identify the following compounds as covalent (two nonmetals) or ionic (a metal & a nonmetal).

a. cacl2
b. h2o
c. nacl
d. ch4
e. libr
f. bao
g. ki

Explanation:

1. The noble - gas group (Group 18) is the most stable on the periodic table because they have a full outer - electron shell, which gives them a stable electron configuration.
2. The most reactive groups are the alkali metals (Group 1) and the halogens (Group 17). Alkali metals are reactive because they have one valence electron and want to lose it to achieve a stable configuration. Halogens are reactive because they need one more electron to complete their outer shell.
3. Electron - dot diagrams represent the valence electrons of an atom as dots around the symbol of the element. Sodium (Na) has 1 valence electron, calcium (Ca) has 2, boron (B) has 3, chlorine (Cl) has 7, and krypton (Kr) has 8.
4. The two types of chemical bonds are ionic and covalent bonds.
5. An ionic bond is a chemical bond formed by the transfer of electrons from a metal to a non - metal, resulting in the formation of ions that are held together by electrostatic forces.
6. A covalent bond is a chemical bond formed by the sharing of electrons between two non - metals.
7. In an ionic bond, electrons are transferred from one atom to another.
8. Ionic bonds involve a metal and a non - metal.
9. An ion with a positive charge is a cation; an ion with a negative charge is an anion.
10. In a covalent bond, electrons are shared between atoms.
11. Covalent bonds involve two non - metals.

12.

• a. CaCl₂: Ionic (calcium is a metal, chlorine is a non - metal).
• b. H₂O: Covalent (hydrogen and oxygen are non - metals).
• c. NaCl: Ionic (sodium is a metal, chlorine is a non - metal).
• d. CH₄: Covalent (carbon and hydrogen are non - metals).
• e. LiBr: Ionic (lithium is a metal, bromine is a non - metal).
• f. BaO: Ionic (barium is a metal, oxygen is a non - metal).
• g. KI: Ionic (potassium is a metal, iodine is a non - metal).

Answer:

1. The noble - gas group (Group 18) is the most stable due to a full outer - electron shell.
2. The most reactive groups are the alkali metals (Group 1) and halogens (Group 17). Alkali metals are reactive as they have one valence electron to lose, and halogens need one more electron to complete their outer shell.
3. Sodium: 1 dot around Na; Calcium: 2 dots around Ca; Boron: 3 dots around B; Chlorine: 7 dots around Cl; Krypton: 8 dots around Kr.
4. Ionic bond, covalent bond.
5. A bond formed by electron transfer from a metal to a non - metal, creating ions held by electrostatic forces.
6. A bond formed by electron sharing between two non - metals.
7. Transferred.
8. A metal and a non - metal.
9. Cation; Anion.
10. Shared.
11. Two non - metals.

12.
a. Ionic
b. Covalent
c. Ionic
d. Covalent
e. Ionic
f. Ionic
g. Ionic