Write a balanced chemical equation based on the following description:
solid chromium reacts with solid iodine to form solid chromium(III) iodide.

2 Cr(s) + 3 I2(s) → 2 CrI3(s)

Explanation:

Reactants:

Solid Chromium

• Chromium is a transition metal with an elemental symbol → Cr

• It can exist as a stable monatomic solid → Cr(s)

Solid Iodine

• Iodine is a non-metal halide of Group 7A → I

• It exists as a diatomic solid → I2(s)

Products:

Chromium(III) iodide

• Chromium, Cr → roman numeral III → +3 charge → Cr3+

• Iodide, I → from group 7A → -1 charge → I-

• When ions combine, their charges or oxidation numbers crisscross to become subscripts

• Cr will have a subscript of 1 from I- → Cr

• I will have a subscript of 3 from Cr3+ → I3

• Subscript 1 is no longer indicated → CrI3(s)

Unbalanced Chemical Reaction: Cr(s) + I2(s) → CrI3(s)

Balancing the chemical reaction:

1. Balance I:

Cr(s) + I2(s) → CrI3(s)

• There are 2 I in the reactant and 3 I in the product side

• Balance I by adding the coefficient 3 in I2 and 2 in CrI2

• There would be a total of 6 I in the reactant and product sides

Cr(s) + 3 I2(s) → 2 CrI3(s)

2. Balance Cr:

Cr(s) + 3 I2(s) → 2 CrI3(s)

• There is 1 Cr in the reactant and 2 Cr in the product side

• Balance Cr by adding the coefficient 2 in Cr(s)

• There would be a total of 2 Cr in the reactant and product sides

2 Cr(s) + 3 I2(s) → 2 CrI3(s)

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.

im pretty sure its b