Answer:
Explanation:
Alkaline earth metals are in group 2. The number of valence electrons of elements in group 2 is 2.
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.
The energy transformations are similar because they result into radiant energy.
As for the lamp, Electrical energy is transformed into light when the filament
or mercury vapor glows on passage of current.
The fire- chemical energy is turned to light energy during the combustion of carbon. Both products comprise of ultraviolet radiation which is a form of radiant energy.
Answer:
B) irreversible process
Explanation:
The process given here is irreversible.
Answer:
The mass number (A), also called atomic mass number or nucleon number, is the total number of protons and neutrons (together known as nucleons) in an atomic nucleus. The mass number is different for each different isotope of a chemical element.
