The atom with 3 protons is lithium (Li) because its atomic number is 3. The electronic configuration of lithium is 2,1, meaning it has one valence electron in its outermost shell. Valency is the number of electrons an atom loses, ...
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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.
The correct answer is: (b) 35.5 u The atomic mass of chlorine is approximately 35.5 u, which is the weighted average of the isotopes chlorine-35 and chlorine-37. This average accounts for their relative abundance in nature. Class 9th Science NCERT ...
(d) valency of each element. The chemical formula of a molecular compound is determined by the valency of each element. The valency indicates how many bonds an element can form, which helps in combining elements in the correct ratio to ...
To find the number of neutrons in sodium (Na) and magnesium (Mg), we subtract the atomic number from the atomic mass: Sodium (Na) has an atomic number of 11 and an atomic mass of 23. Neutrons = 23 – 11 ...
The molecular mass of glucose (C6H12O6) is calculated by adding the atomic masses of its constituent atoms: 6 carbon (12 u), 12 hydrogen (1 u), and 6 oxygen (16 u). This gives a total of 180 u. So, the correct ...