Which element is found in period 3, group 2?
2 answers:
Answer: Magnesium (Mg)
Explanation:
I attached a copy of a periodic table for reference.
When we look at the periodic table, go across to group 2 (Alkali Earth Metals) and then down to period 3, where we find Magnesium.
Interestingly, we could also gain this information from Magnesium's spdf electronic configuration: 1s²2s²2p⁶3s². With this, '3' tells us the period, and '²' tells the group.
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Answer:
Fr = 20 (N)
Explanation: See atached file ( free body diagram)
As for Newton´s low
∑ Fy = 0
-mg + N = 0 ⇒ - 40 + N = 0 ⇒ N = 40 [Newtons]
by definition : Fr = μs * N ⇒ Fr = 0,5 * 40 ⇒ Fr = 20 (N)
∑ Fx = 0 body is at rest
Fe - Fr = 0
Fr > Fe
Fr > 12 (N) the body is at rest
