Which of the following statements is/are CORRECT for an oxyg…

Which of the following statements is/are CORRECT for an oxygen atom? 1. The effective nuclear charge felt by a 2s electron is greater than that felt by a 1s electron. 2. The effective nuclear charges felt by 2s and 2p electrons are identical. 3. The effective nuclear charge felt by a 2p electron is less than that felt by a 2s electron.