The correct answer is:
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" F and Br , because they are in the same group" .
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Note:
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Choice [B]: "F and Br ; because they are in the same period" ; is incorrect; since "F" and "Br" are not in the same "period" (that is, "row").
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Choice [C]: "Na and Mg; because they are in the same group {"column"} ; is incorrect; since: "Na" and "Mg are NOT in the same group {"column"].
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Choice [D]: "Na and Mg" ; because they are in the same period {"row"}; is incorrect. Note: "Na" and "Mg" are, in fact, in the same period {"row"}. However, as aforementioned, {Mg and Na} are not in the same group {"column".}.
Note: The similiarities in physical and chemistry properties among elements are determined and organized — or tend to be so—by "groups" {"columns"} — NOT by "periods" {rows}.
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Following laboratory safety protocols such as wearing personal protective equipment will protect John when the accident occurred.
<h3>What are laboratory safety protocols?</h3>
Laboratory safety protocols are the protocols put in place to ensure safety in the laboratory.
Laboratory safety protocols include the following:
- always wear personal protective equipment in the laboratory
- do not play in the laboratory
- do not eat in the laboratory
Following laboratory safety protocols will help protect us from accidents which occur in the laboratory.
What happened when john was carefully pouring a chemical into a beaker when the beaker slips and breaks is an example of laboratory accident.
Wearing personal protective equipment will protect John.
In conclusion, following laboratory safety protocols will protect us when accidents occur in the laboratory.
Learn more about laboratory safety protocols at: brainly.com/question/17994387
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Note that the complete question is given as follows:
John is carefully pouring a chemical into a beaker when the beaker slips and breaks. How would laboratory safety protocols help John?
Hydrogen and oxygen cn form a polar covalent bond