Final answer:
The placement of elements on the periodic table determines their electron configuration. For example, calcium (Ca) should end with s² ([Ar]4s²), while tin's (Sn) configuration ends with p² ([Kr]5s² 4d10 5p²). The row of an element indicates its number of electron shells and how they're filled, like sodium (Na) with 1s² 2s² 2p⁶ 3s¹.
Step-by-step explanation:
When predicting the electron configuration of an element based on its position on the periodic table, it is essential to understand the order in which electrons fill the subshells. For calcium (Ca), we can determine that it is located in the second column of the s block of the periodic table, which implies that its outermost electron will occupy the s-orbital. Hence, the electron configuration for calcium should indeed end with s², and the complete electron configuration is [Ar]4s².
Similarly, the placement of tin (Sn) in the periodic table is in the second column of the p block. This indicates that the ending part of tin's electron configuration should include a p² orbital. The complete electron configuration for tin is [Kr]5s² 4d10 5p².
The periodic table also informs us about the number of electron shells an element has based on the row it's located in. The columns from left to right increase the number of electrons within those shells. For small atoms, the first two electrons fill the 1s subshell, the next two fill the 2s subshell, followed by six in the 2p subshell. Applying these rules to sodium (Na), we find that its electron configuration would be 1s² 2s² 2p⁶ 3s¹, which correlates with its position in the periodic table.