Chemistry
What happens to atomic radius from left to right across the periodic table?
It decreases because the increasing nuclear charge pulls the electrons closer.
What is the difference between ionic bonds and molecular/covalent bonds?
Ionic bonds are between non-metals and metals, transfer electrons to become stable and neutral, and have higher melting/boiling points and conductivity when dissolved or melted.
Molecular/covalent bonds are between two non-metals, share electrons to become stable and neutral, have lower melting/boiling points and do not conduct electricity.
What were Bohr and Rutherford’s role in the planetary model and why is it referred to as a Bohr-Rutherford diagram?
Rutherford discovered there is a solid nucleus in the center of an element because a particle hit the nucleus and bounced back, and when passing through it came out in a different direction due to the gravitational pull of the nucleus.
Bohr discovered the orbitals inside of an atom, stating that electrons travel in specific fixed energy around a center nucleus.
What happens to the reactivity of elements moving down group 1 as compared to moving down group 17?
Alkali metals increase in reactivity down the group, because they react by losing a single valence electron. As more shells are added, the electron becomes farther from the nucleus and therefore easier to lose.
Halogens decrease in reactivity because they react by gaining one valence electron. As more shells are added, the valence shell becomes farther from the nucleus and therefore farther from the nucleus’s attraction which attracts the extra electron.