The correct answer is (b) 2,8,2. Magnesium (Mg) has an atomic number of 12, meaning it has 12 electrons. The electronic distribution follows the 2,8,2 pattern according to the Bohr model, where the first shell holds 2 electrons, the second ...

The correct answer is (c) different neutrons. Isotopes of an element have the same number of protons and electrons but different numbers of neutrons. This results in the same chemical properties but slightly different physical properties, such as mass and ...

The correct answer is (a) An atom has an equal number of electrons and protons. Atoms are electrically neutral, meaning the number of protons (positively charged) always equals the number of electrons (negatively charged). However, the number of neutrons may ...

The correct answer is (c) The two oxygen atoms are isotopes. Isotopes of an element have the same number of electrons and protons but different numbers of neutrons. In ethyl ethanoate (CH₃COOC₂H₅), both oxygen atoms belong to the same element ...

Non-metals like fluorine (F), chlorine (Cl), and bromine (Br), which gain one electron to form negative ions (anions). Thus, elements with valency 1 are not always metals or non-metals but can be either. Class 9th Science NCERT MCQ Questions NCERT ...