The atomic number of beryllium (Be) is 4, and the atomic number of barium (Ba) is 56. the <span>comparison is best supported by this information is that beryllium has a lower atomic radius than Barium</span>
<em>They are in the same group because they have similar chemical properties, but they are in different periods because they have very different atomic numbers.</em>
<h3><u>Explanation;</u></h3>
<em><u>Beryllium (Be) is an element is the periodic table with an atomic number of 4, which means it has 4 protons in the nucleus and also 4 electrons in the energy levels, since the number of protons is equal to the number of electrons.</u></em>
Beryllium has an electron configuration of 2: 2, which means it has two valence electrons, and has two energy levels which means<em><u> it occupies period two of the periodic table, and group two of the periodic table.</u></em>
Barium (Ba) on the other had, has an atomic number of 56, which means it has 56 protons and 56 electrons. Thus it has an electron configuration of; 2;8;18;18;8;2; this shows that<u><em> it has 6 energy levels thus occupies period 6 and is in group two since it has two valence electrons. </em></u>
