The mass number of aluminium is 26 and the atomic number of aluminium is 13.
The number of neutrons is given by the difference between the mass number and number of protons.
number of neutrons = mass number - number of protons
Number of protons = 13
Mass number of Aluminium = 26
Therefore number of neutrons = 26-13 = 13.
The atomic number of thorium is 90 and the mass number of thorium is 230 as given in the question
atomic number = number of electrons = number of protons
Therefore the number of electrons in thorium 230 = 90
Number of protons in thorium 230 = 90
Number of neutrons = Mass number - number of protons = 230-90 = 140
<span>It contains 6.02mc001-2 particles of a given substance</span>
The energy released when electron move from n=4 to n=3 is 0.66 eV
We know that in an atom energy of nth state is
eV
where n is the energy level
Therefore,

Thus,
= -0.85eV
= -1.51eV
Therefore, total mount of energy released in moving electron from n=4 to n=3 is given by -

= -0.85 - ( -1.51)
= 0.66eV
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Answer:
4.03dm³
Explanation:
The reaction expression is given as:
3H₂ + N₂ → 2NH₃
Volume of hydrogen = 12dm³
AT rtp:
1 mole of gas occupies volume of 22.4dm³
x mole of hydrogen will occupy a volume of 12dm³
Number of moles of hydrogen =
= 0.54mole
From the balanced reaction equation:
3 mole of hydrogen gas combines with 1 mole of Nitrogen gas
0.54 mole of hydrogen as will therefore combine with
= 0.18moles of nitrogen gas
Since ;
1 mole of gas occupies a volume of 22.4dm³
0.18moles of Nitrogen gas will occupy 0.18 x 22.4 = 4.03dm³