Here is the answer for the three of them
<span>N20 = 16 e-
</span><span>SeCl2 =20
</span><span>PBr3 = 26
Remember that t</span><span>o find the valence electrons in an atom you need to identify what group the element is in. An element in group 1A has 1 valence electron. If the element is in group 2A, then it has two valence electrons.</span>
The answer is: <span>supersaturation</span>
<span>2.188*10^23 atoms of iron
6.022*10^23 atoms/mole
(2.188*10^23 atoms of iron)/(6.022*10^23 atoms/mol)~.3633 moles of iron
Hope this helps!</span>
A change which would remove the source of this error is to: Test a fourth group, in which participants do not receive the mineral supplements.
<h3>What is a scientific method?</h3>
A scientific method can be defined as the various techniques that are adopted to observe, investigate, examine and study a particular thing while giving explanations on the basis of the evidence, theory, proof, hypothesis, or factual information they derived from the research work.
In this scenario, a claim was made by the company its mineral supplements can effectively prevent common cold. However, this claim was disputed by a scientist because there exist an error in the group setup.
<h3>How to remove an error in science</h3>
For this investigation, an effective and efficient way to remove this source of error would be by testing a fourth group, in which the mineral supplements is not administered to any of the participants.
Read more on scientific method here: brainly.com/question/17216882
