The atomic number of aluminium is 13, meaning it has 13 electrons. The electrons are arranged in shells following the 2, 8, 3 distribution: 2 electrons in the first shell, 8 in the second, and 3 in the third. So, ...

The correct answer is:(c) nucleus in the atom Rutherford’s α-particle scattering experiment demonstrated that the positive charge and most of the mass of an atom are concentrated in a small central nucleus. This led to the discovery of the atomic ...

The correct answer is: (b) (ii) and (iv) Rutherford’s α-particle scattering experiment led to the following conclusions: (ii) The mass and positive charge of the atom are concentrated in a small central nucleus. (iv) Most of the space in an ...

The correct answer is: (a) (i) and (iii) Rutherford’s model of the atom considered the nucleus as positively charged (i), and it can be compared to the solar system (iii), with electrons orbiting the nucleus like planets orbiting the sun.

The incorrect statement is: (d) An isotope of magnesium is used in the formation of chlorophyll. Magnesium itself (not its isotope) is essential in the formation of chlorophyll, but the isotope of magnesium is not specifically used in this process.