Using the law of constant proportions which says that within the same compound, elements exist in fixed ratios.
Therefore; we can use the ratio of total mass to the mass of carbon, to determine the amount of carbon in another sample.
Mass C / Mass CH4 = Mass C / Mass CH4
43.2 g / 57.6 g = Mass C / 37.8 g
Mass C = 37.8 g × 43.2 g / 57.6 g
= 28.35 g
Hence; the percentage of carbon will be;
=(28.35/ 37.8 )× 100%
= 75 %
Thus; 75% of 37.8 g of methane is carbon
Unstable, radioactive atom emits alpha and gamma ray to transform into a stable atom.
Emitting an alpha particle, decreases the mass number by four and atomic number by two.
Emitting gamma ray reduces the excess energy of the radioactive atom.
Rutherford theorized that atoms have their charge concentrated in a very small nucleus.
This was famous Rutherford's Gold Foil Experiment: he bombarded thin foil of gold with positive alpha particles (helium atom particles, consist of two protons and two neutrons).
Rutherford observed the deflection of alpha particles on the photographic film and notice that most of alpha particles passed straight through foil.
That is different from Plum Pudding model, because it shows that most of the atom is empty space.
According to Rutherford model of the atom:
1) Atoms have their charge concentrated in a very small nucleus.
2) Major space in an atom is empty.
3) Atoms nucleus is surrounded by negatively charged particles called electrons.
4) An atom is electrically neutral.
