Quintal definition: a unit of weight equal to 100 pounds | Meaning, pronunciation, translations and examples English Dictionary | Thesaurus | Translator | Grammar | Scrabble | Blog English
Electrons in a hydrogen atom must be in one of the allowed energy levels. If an electron is in the first energy level, it must have exactly -13.6 eV of energy. If it is in the second energy level, it must have -3.4 eV of energy. An electron in a hydrogen atom cannot have -9 eV, -8 eV or any other value in between. Let's say the electron wants to jump from the first energy level, n = 1, to the second energy level n = 2. The second energy level has higher energy than the first, so to move from n = 1 to n = 2, the electron needs to gain energy.
As the atomic number increases from left to right across the row, or 'period', the effective nuclear charge felt by. the valence electrons also increases and so they are more tightly held, resulting in an increase in the first. ionisation energy (figure 1). This is not entirely linear, with a few peaks and troughs.