Question

question 27 of 39 what is the chemical formula for the compound formed between sodium and bromine? formula: what is the chemical formula for the compound formed between sodium and selenium? formula:

Explanation:

First Sub - Question (Sodium and Bromine)

Step1: Determine ion charges

Sodium (Na) is in Group 1 of the periodic table, so it forms a \(Na^{+}\) ion (loses 1 electron). Bromine (Br) is in Group 17, so it forms a \(Br^{-}\) ion (gains 1 electron).

Step2: Balance charges

To form a neutral compound, the number of positive and negative charges must be equal. Since the charge of \(Na^{+}\) is +1 and \(Br^{-}\) is - 1, we need 1 \(Na^{+}\) and 1 \(Br^{-}\) to balance the charges.

Step3: Write the formula

Using the ion symbols, the formula is \(NaBr\) (we write the cation first, then the anion, and the subscripts are 1 when the charges balance in a 1:1 ratio).

Second Sub - Question (Sodium and Selenium)

Step1: Determine ion charges

Sodium (Na) forms \(Na^{+}\) (charge +1). Selenium (Se) is in Group 16, so it forms \(Se^{2 -}\) (gains 2 electrons, charge - 2).

Step2: Balance charges

Let the number of \(Na^{+}\) ions be \(x\) and \(Se^{2-}\) ions be \(y\). We need \(x\times( + 1)+y\times(-2)=0\). Solving for the smallest whole - number ratio, if \(y = 1\), then \(x = 2\) (because \(2\times(+1)+1\times(-2)=0\)).

Step3: Write the formula

Using the ion symbols, with 2 \(Na^{+}\) ions and 1 \(Se^{2-}\) ion, the formula is \(Na_{2}Se\).

Answer:

For the compound between sodium and bromine: \(NaBr\)
For the compound between sodium and selenium: \(Na_{2}Se\)