Put the following elements in order of increasing first ionization energy: Ca, O, B, Be
Ca < Be < B < O
Be < B < O < Ca
O < B < Be < Ca
Ca < O < B < Be
https://www.angelo.edu/faculty/kboudrea/periodic/trends_ionization_energy.htm
Ca<Be<B<O
To determine the order of increasing first ionization energy for the elements Ca, O, B, and Be, we need to understand what first ionization energy is.
First ionization energy is defined as the energy required to remove the outermost (valence) electron from an atom in its gaseous state. Elements with higher first ionization energy tend to have stronger attraction between the nucleus and the outermost electron, and thus, it is more difficult to remove the electron.
To order these elements in increasing first ionization energy, we can look at their atomic structure and the trends within the periodic table.
1. Be (Beryllium) - Be has an atomic number of 4. It has two valence electrons in the 2s orbital. Being an alkaline earth metal, Be has a relatively low first ionization energy compared to the other elements in the list because its valence electrons are closer to the nucleus and less shielded by inner electrons.
2. B (Boron) - Boron has an atomic number of 5. It has three valence electrons in the 2s2 2p1 orbital. Boron is a nonmetal and has a higher first ionization energy than beryllium due to its smaller atomic size and greater nuclear charge.
3. O (Oxygen) - Oxygen has an atomic number of 8. It has six valence electrons in the 2s2 2p4 orbital. Oxygen is a highly electronegative nonmetal and has an even higher first ionization energy than boron because it requires more energy to remove one of its paired electrons from a stable electron configuration.
4. Ca (Calcium) - Calcium has an atomic number of 20. It has two valence electrons in the 4s2 orbital. Calcium is an alkaline earth metal and has the lowest first ionization energy on this list. This is because the outermost valence electrons are located in a higher energy level (4s) and are relatively shielded by inner electrons.
Based on this information, the correct order of increasing first ionization energy is:
Be < B < O < Ca