Final answer:
The element with electron configuration 2-8-18-1 is potassium (K), which is in the first column of the s-block of the periodic table and has an atomic number of 19.
Step-by-step explanation:
An element whose atoms have the electron configuration 2-8-18-1 is likely a member of the alkali metals which reside in the first column of the s-block. The mentioned configuration suggests that this element has 29 electrons. Referring to the periodic table and electron configurations chart, we can determine that the element with this configuration is potassium (K), which has an atomic number of 19. Potassium typically has the electron configuration of 1s² 2s² 2p¶ 3s² 3p¶ 4s¹, which is the same as having the configuration 2-8-8-1 when considering each shell's capacity without specifying subshell orbitals.