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State and explain the trend in atomic radius down a group of the periodic table

Down a group of the periodic table, the atomic radius increases. As we go down a group, the outermost electron of an atom is placed in a shell that is further from the nucleus. This means it experiences the ...
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Answered by Thomas C. • Chemistry tutor
38419 Views

How do you find the roots of a cubic equation?

Solving cubics is an interesting problem: while there is a formula which can find the roots of every cubic equation, it isn't taught and is not generally worth learning. Instead, exam questions will often gi...
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Answered by Sam M. • Maths tutor
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How many diagrams is it best to use in an extended essay?

It's a common misconception that more diagrams are always better. In fact, a diagram that is ill-defined or poorly linked to the question will not add anything to your answer and it can demonstrate a lack of...
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Answered by David C. • Economics tutor
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Let f(x) and g(x) be two odd functions defined for all real values of x. Given that s(x)=f(x)+g(x), prove that s(x) is also an odd function.

We recall that a function f(x) is said to be an odd function when f(-x)=-f(x) . We are told that f(x) and g(x) are odd functions, so we know from the above definition that: 1. f(-x)=-f(x) 2. g(-x)=-g(x) Solu...
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Answered by Keir H. • Maths tutor
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Two electrons are a distance r apart, the first electron exerts a force F on the second electron. a) What force does the second electron exert on the first? b) In terms of r, at what distance is the force that the first electron exerts on the second F/9?

This question is on electric forces between charged particles. A useful equation to consider is Coulomb's law: F=k(Q 1 Q 2 )/R 2 Where k is the Coulomb's law constant:k~9.0x10 9 Nm 2 /C 2 Q is the charge on ...
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Answered by Ross W. • Physics tutor
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