Try photo math it will probably be more helpful
Answer:
Na₂SO₃
Explanation:
We can use the <em>criss-cross method</em> to work out the formula.
1. Write the <em>symbols</em> of the anion and cation.
Na¹⁺ SO₃²⁻
2. <em>Criss-cross the numbers of the charge</em>s to become the subscripts of the other ion (see image).
3. Write the formula with the <em>new subscripts</em>.
Na₂(SO₃)₁
4. Omit all subscripts <em>that are 1.</em>
The formula becomes Na₂SO₃.
Compounds that has two elements on the formula can be bonded by ionic or covalent bond. If the compound is a metal and a non-metal then it will be ionic bonding. However, when it involves two non-metals, then it will have covalent bonding.
The number 345,000 has 3 significant figures because the trailing zeros are not significant since there's no decimal point.
<h3>What is significant figures?</h3>
Significant figures of a number in positional notation are digits in the number that are reliable and necessary to indicate the quantity of something.
Also significant figures can be defined as, the number of digits in a value, often a measurement, that contribute to the degree of accuracy of the value.
Examples of significant figures;
- 405 = 3 significant figures
- 405000 = 3 significant
- 0.040500 = 5 significant figures
<u>Note:</u> leading zeros are not significant but trailing zeros, which are zeros at the end of a number, are significant only if the number has a decimal point.
345,000 = 3.45 x 10⁵ (3 significant figures)
Thus, the number 345,000 has 3 significant figures because the trailing zeros are not significant since there's no decimal point.
Learn more about significant figures here: brainly.com/question/24491627
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I assume that the answers would be
2) is "A"
3) is "D"
