Why does the first ionisation energy of atoms generally increase across a period?
The first ionisation energy is defined as the energy required to remove one mole of electrons from each atom of a mole of gaseous atoms. As we go along a period in the periodic table, the atomic number increases. As the atomic number increases, the number of protons in the nucleus increases. This causes the electrostatic attraction between the nucleus and the outermost electron to generally become stronger across a period.
Related Chemistry A Level answers
All answers ▸Which liquid would you expect to have a higher boiling point, Bromine (Br2) or Iodine I2)? Explain your answer.
Explain the variation of atomic radius along a period and along a group of the Periodic Table
Describe and explain the trend in boiling points in the first four hydrogen halides
Describe a test that could be used to distinguish between potassium sulfate (K2SO4) and potassium nitrate (KNO3)