Arrange in order of increasing atomic size
the Period 2 elements Be, Li, and Ne
Look up their atomic numbers (Google maybe?)
arrange in that order
Anonymous does it the easy way; however, you can think your way through it, too. In the same period (row), all of the electrons are going into the same outer orbit, therefore, the distance is generally the same from the nucleus BUT the nucleus is increasing in positivity due to increasing the number of protons. Therefore, the outer electrons are more strongly attracted inwardly and the radius of the atom decreases. So for the Li, Be, Ne series you would expect Ne to be the smallest and Li to be the largest. Hope that agrees with the google numbers when you look up those values.
To arrange the Period 2 elements Be (beryllium), Li (lithium), and Ne (neon) in order of increasing atomic size, you need to compare their atomic numbers. The atomic number increases from left to right across the periodic table.
1. Li (atomic number 3): Lithium has the smallest atomic number among the three elements, so it has the smallest atomic size.
2. Be (atomic number 4): Beryllium comes next with a slightly larger atomic number, making it larger in size compared to lithium.
3. Ne (atomic number 10): Neon has the largest atomic number among the three elements, making it the largest in atomic size.
Therefore, the order of increasing atomic size is Li < Be < Ne.