Answer:
We typically represent covalent bonds with a dash ( - ) between the atoms. This indicates a single bond. Ex: Cl - Cl
Single bond, double bond, triple bond.
Explanation:
We call it a single covalent bond because the atoms are sharing a single pair of electrons.
Let's eliminate these one by one.
The first pair would not be the same, as X would most likely be in group IA, and Y would be in group VIIA, because of their tendency to gain and lose electrons.
The second pair would also violate the same rule, but X would most likely be in group IIA, and Y would most likely be in group VIA.
The third pair would not be the same, as X is most likely in group VIIA, and since Y has eight valence electrons, it is most likely a noble gas.
The final pair has X with atomic number 15, making it phosphorous. Phosphorous wants to gain 3 electrons to have a full octet of 8 outer "valence" electrons, and Y would also like to gain 3 electrons. This means it is possible that the final pair would be in the same group.
Answer: 3 significant figures
Explanation: because in scientific notation only the before and after decimal number are considered but in standard form all numbers including exponents are all significant figures
Ok measure atoms the answer is B