Compare and contrast the periods and groups on the Modern Periodic Table.
Answers
Explanation:
Groups (families) are columns in the periodic table. All elements in a group have a similar arrangement in their outermost electrons (valence electrons). Because of the similar electron arrangements, elements in a group have similar chemistry and tend to react and form similar products, just the kinetics tends to be different due to changes in reactivity. Metals tend to be more reactive towards the bottom of a group and non-metals toward the to of the group.
A period is a row in the periodic table. One way to think about a period is that it is an energy level with space for all of the electrons of a given energy level. The first period (lowest quantum number) only has space for two electrons in its one s orbital. The second period has room for 8 electrons (2 in 2s and 6 in 2p), the third energy level has room for 18 electrons (2in 3s, 6 in 3p and 10 in 3 d). However the third period only has 8 elements whereas the 4 period has 18.Why? The order of filling the atomic orbitals is from the lowest energy to the highest and the energy required to fill the 3D orbitals is inbetween the 4s and 4p orbitals so it is located in the 4th period.
What are the consequences of all of this organization across a period? Elements on the left side of a period have relatively large atomic radii and as you go across a period to the right, the number of protons increases but electrons are placed in the same energy level. The increased attractive force of the nucleus causes the atomic radii to decrease. This has effects on the way elements react. Those one the left have their outermost electrons losely held and they react by losing electrons (a property of metals in ionic compound formation) whereas the ones on the right react by acquiring electrons (a property of non-metals in Ionic compound formation).