Final answer:
An atom with 2k and 8l electrons has an electronic configuration of 1s² 2s² 2p¶, filling three subshells - the 1s, 2s, and 2p subshells.
Step-by-step explanation:
An atom with 2k and 8l electrons has an electronic configuration that is built by filling up electron orbitals from the lowest energy levels upwards. According to the Aufbau principle, we start with the 1s orbital and move to higher orbitals. The first 2 electrons will fill the 1s orbital, giving us a configuration part of 1s².
The next 2 electrons fill the 2s orbital, so we have 1s² 2s². Since the 'k' indicates potassium (with atomic number 19) and the 'l' indicates the 12th element (magnesium with atomic number 12), we are probably looking at a theoretical atom with a combined total of 2+8=10 electrons in the configuration. Following the 2s orbital, we would fill the 2p orbital which can hold up to 6 electrons, thus the remaining 6 electrons give us 1s² 2s² 2p¶. This configuration has a total of 3 subshells: one 1s subshell, one 2s subshell, and one 2p subshell. Each subshell corresponds to a unique set of quantum numbers and energy state for the electrons residing there. Therefore, the total number of subshells for this electron configuration is three.