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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Answer:
it causes alot of harm to the earth.
Explanation:
earthquakes
an so on
They are examples of physical<span> contaminants .</span>
To answer the question above, substitute the given values to the given equation,
Q(t) = Q x e^-kt
12 grams = (36 grams) x e^(-0.00011)(t)
Solving for t gives t = 9,987.38 years or approximately equal to 9,990 years. Thus, the answer is letter C.
Answer is: the average atomic mass is 232.
ω₁ = 20% ÷ 100%.
ω₁ = 0.20.
ω₂ = 80% ÷ 100%.
ω₂ = 0.80.
Ar₁ = 120 (number of protons) + 120 (number of neutrons).
Ar₁ = 240.
Ar₂ = 120 + 110
.
Ar₂ = 230.
Average atomic mass of atoms of bolognium =
Ar₁ · ω₁ + Ar₂ · ω₂.
Average atomic mass of atoms of bolognium = 240 · 0.2 + 230 · 0.8.
Average atomic mass of atoms of bolognium = 48 + 184.
Average atomic mass of atoms of bolognium = 232.
