如何判斷元素週期表的趨勢 (Trend of the periodic table)

如何判斷元素週期表的趨勢 (Trend of the periodic table)

我們都知道,元素週期表是根據原子序以小而大與電子組態來做排列順序,但一張元素週期表裡面,其實還有很多有趣的趨勢。

比如,為什麼在同一個週期(Period)裡面,有左而右原子序依序遞增,但是原子大小卻是越來越小呢?照理說原子序越大,意味著原子量越大,原子應該是越來越大顆,可是半徑反而變小呢?

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《AP Calculus》A plane flies horizontally at an altitude....Find the rate of the plan travels at some time

Question:

A plane flies horizontally at an altitude of 5 km and passes directly over a tracking telescope on the ground. When the angle of elevation is π/3, this angle is decreasing at a rate of π/6 rad/min. How fast is the plane traveling at that time?

Solutions:

這是典型的 Related rate problem,答題方式很簡單,基本上有一套SOP

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