Answer:
At earlier times elements were arrangrd on the basis of their atomic masses to study their properties easily but there were various problems like isotopes needs different position in perodic table.
After discovery of atomic number modern periodic table was created on the basis of atomic number (number of proton) that is unique for each element and varies regularly. So study of a group of elements is much easier than each element seperately that is why modern periodic table was formed.
Explanation:
Answer:
λ=2167.6 nm
The wavelength of light emitted is 2167.6 nm.
Explanation:
We recall that Eₙ=
since there was transition from n7 to n=4 we will first calculate the change in the energy i.e ΔE
ΔE=E₄-E₇
ΔE=
ΔE=-9.1760*10^-20 J
Now:
|ΔE|=Energy of photon=h*v=h*c/λ
λ=h*c/|ΔE|
λ=
λ=2.1676*10^-6 m
λ=2167.6*10^-9 m
λ=2167.6 nm
The wavelength of light emitted is 2167.6 nm.
Answer: Matter is heated, and its particles spread out more
Explanation:
Thermal expansion occurs when there's an expansion of an object or material or when an object becomes bigger because of a rise in its temperature. This brings about the faster movement of the heated molecules and the atoms spreading out.
Therefore, the cause and effect of thermal expansion will be that when matter is heated, and its particles spread out more.
Number of moles = mass of product / molecular mass
=mass of product (MgO) / 40.3
Since the mass of MgO is not given in the question, the correct answer choice cannot be given. However, proceeding witht eh above formula will enable you to find the correct number of moles given the mass of MgO.
Answer:
the answer would be A. cells
Explanation:
just trust me Im a 8th grader and I did that before
