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Explain why the first ionisation energy of Strontium is less than the first ionisation energy of Calcium

Both of these elements are part of the 2nd group of elements on the periodic table. ie in first ionisation, their electron configuration changes from nS2 -> nS1. Strontium is a much larger element, so the...
OH
Answered by Olivia H. • Chemistry tutor
10972 Views

Given y=x^3-x^2+6x-1, use diffferentiation to find the gradient of the normal at (1,5).

dy/dx = 3x^2-2x+6 At (1,5), dy/dx = 7. 7 is the gradient of the tangent, therefore the gradient of the normal at (1,5) is -1/7.
KR
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What is the present subjunctive and when is it used?

The subjunctive is a ' mood ', not to be confused with ' tense ' since a mood can have more than one tense. The present form of the subjunctive is the most common in French today; there is also an imperfect ...
TJ
Answered by Tabitha J. • French tutor
5137 Views

How can you tell the difference between a right-handed and left-handed coil (or helix) by looking at it?

Portions of proteins can arrange in regularly repeating structures such as α-helices: the vast majority of these helices are right-handed (the left-handed versions are very rare). Similarly, DNA (double) hel...
RS
Answered by Riccardo S. • Science tutor
28507 Views

What is the sliding filament mechanism?

The sliding filament mechanism is a model used to show the way in which muscles contract. It involved 3 components - Myosin, Actin and Tropomyosin. Myosin has a head like projection to which an ADP molecule ...
JC
Answered by Joseph C. • Biology tutor
12876 Views