Which change of phase is endothermic chem test.

☆ionisation energy increases across a period from na -> ar☆ionisation energy decreases down a group from li -> fr☆ionic radius decreases across a period from na -> cl☆ionic radius increases down a groupfrom f -> ii hope it clarifies your doubts

The answer is accuracy

Six base units were recommended: the metre, kilogram,second, ampere, degree kelvin (later renamed kelvin), and candela. in 1960, the 11th  cgpm  named the system the international system of units, abbreviated si from the french name, le système international  d'unités.