Structure of At...

General electronic configuration of  outermost and penultimate shell is  $$(n-1)s^{2}(n-1)p^{6}(n-1)d^{x}ns^{2}$$  If n = 4 and x = 5,  then number of protons in  the nucleus will be :- 

Write the S.I. unit of activity.

What mass of solid ammonium carbonate $$H_2NCOONH_4$$, when vaporized at $$273^oC$$, will have a volume of $$ 8.96\ 1$$ at $$760\ mm$$ of pressure. Assume that the solid completely decomposes as
$$H_2NCOONH_4(s)\to CO_2(g)+2NH_3(g)$$  

Twenty molecular of $$SO_3$$ will weight as much as _____ molecular of oxygen.

How many spectral line of balmer series present in visible region?

The commonly used pain reliever, aspirin, has the molecular formula $$C_9H_8O_4.$$ If a sample of aspirin contains $$0.968\ g $$ of carbon, what is the mass of hydrogen in the sample?

When a mixture of aluminium powder and iron $$(III)$$ oxide is ignited, it produces molten iron and aluminium oxide. In an experiment, $$5.4\ g$$ of aluminium was mixed with $$18.5\ g$$ of iron $$(III)$$ oxide. At the end of the reaction, the mixture contained $$11.2\ g$$ of iron, $$10.2\ g$$ of aluminium of unreacted iron $$(III)$$ oxide. No aluminium was left. What is the mass of the iron $$(III)$$ oxide left?

Which statement about a $$3$$p orbital is correct?

What is the nucleos number of an atom?

If rocket were fuelled with kerosene and liquid oxygen, what mass of oxygen would be required for every liter of kerosene? Assume kerosene to have the average composition $$C_{14}H_{30}$$ and density, $$0.792\ g/ml$$.