Bohr Model Of The Atom

  ❒ Rutherford’s nuclear model simply stated that atom had a nucleus and the negative electrons were present outside the nucleus. It did not say anything as to how and where those electrons were arranged. It also could not explain why electrons did not fall into the nucleus due to …

Read More »

Photoelectric Effect and Compton Effect

  Photoelectric Effect ❒When a beam of light of sufficiently high frequency is allowed to strike a metal surface in vacuum, electrons are ejected from the metal surface. This phenomenon is known as Photoelectric effect and the ejected electrons Photoelectrons.  ❒For example, when ultraviolet light shines on Cs (or Li, …

Read More »

Atomic Spectrum of Hydrogen

  Atomic Spectra ❒When an element in the vapour or the gaseous state is heated in a flame or a discharge tube, the atoms are excited (energised) and emit light radiations of a characteristic colour. The colour of light produced indicates the wavelength of the radiation emitted.       …

Read More »

Atomic Number – Mass Number

  Mosley’s Determination of Atomic number ❒ The discovery that atom has a nucleus that carries a positive charge raised the question : What is the magnitude of the positive charge? This question was answered by Henry Mosley in 1913. ❒ Hitherto atomic number was designated as the ‘position number’ …

Read More »

Conformations of Cyclohexane: The Chair and the Boat

  Conformations of Cyclohexane: The Chair and the Boat ❒ Cyclohexane is more stable than the other cycloalkanes we have discussed, and it has several conformations that are important for us to consider. (1) The most stable conformation of cyclohexane is the chair conformation. (2) There is no angle or torsional …

Read More »

Acidity: Carboxylic Acids versus alcohols

    ❒ Carboxylic acids are weak acids, typically having pKa values in the range of 3–5. Alcohols, by comparison, have pKa values in the range of 15–18, and essentially do not give up a proton unless exposed to a very strong base. ❒ To understand the reasons for this difference, let’s consider acetic acid …

Read More »