D what is octate ? mention the number of groups and periods in modern periodic table
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D

Explanation:

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octet is a rule. It explains that the outer most electron of an atom should have eight electrons.

groups and 18 periods are present in the modern periodic table

answer: semi-infinite solid initially at a uniform temperature of 400 ◦c is cooled at its surface by convection. the cooling fluid at a constant temperature of 200 ◦c has a convective coefficient (ha) of 250 w/m2.k. the physical properties of the solid: k = 20 w/m.k and α = 4 * 10-5  m2/s. using δx = 0.04 m and δt = 10 s. write the finite difference equations describing the transient heat transfer of the first five δx and the temperature profile after 30 s.