As atomic number increases atomic radii also increase down group 1. ionisation energy down group 1 will also decrease because as atomic radii gets bigger there is less electrostatic force between nuclei and electrons so less energy needed to remove valence electron.
The boiling point (or condensation point) of a substance is defined as the temperature at which the vapor pressure of the liquid is exactly equal to the external pressure. Above the boiling point, the substance exists as a gas and below, it exists predominately as a liquid.
Answer:
There are five signs of a chemical change:
Colour Change.
Production of an odour.
Change of Temperature.
Evolution of a gas (formation of bubbles)
Precipitate (formation of a solid).
