Warmup 1) Are magnesium and calcium in the same group, or the same period? 2) Are beryllium and oxygen in the same group, or the same period? 3) Write the electron configuration for magnesium. Identify the energy level and orbital for the highest-energy electron.

Periodic Table Trends and Bonding Today we will learn about supervising your children at the grocery store, as well as proper ways to share popcorn, and the land of rainbows and unicorns

1) # protons in the nucleus 2) Distance of e-from the nucleus 3) Shielding by inner e- Factors Influencing Periodic Trends:

As you go down a group, atomic radius _______ because ____________ increases: each atom has an additional energy level H Li Na K Rb Atomic Radius: the distance between the atomic nuclei and the furthest electron orbital

Across a period, atomic radius _______ because ______________________ decreases: even though there are additional electrons, the number of energy levels are the same. The nuclear charge (# protons increases, so the e- cloud is pulled in closer NaMgAlSiPSClAr

Which has the largest A.R, Mn, Tc, Re? All are in same group AR increases down a group Rhenium has the largest AR because it has more layers of electrons (closest to Fr!) Which has the smallest A.R, Ge, As, Se? All are in the same period AR increases right to left across a period Selenium has the smallest AR; more + charge inside the nucleus, holds its e- more tightly than As and Se 2 Questions, 2 Minutes!

Francisco Francium: rich chunky guy, easygoing and generous Florence Fluorine: skinny, short, angry, demanding

Li Be B ionization energy is the energy required to remove an electron from a neutral atom IE _____ as you go across a period because ____ increases: nuclear charge increases IE _____ as you go down a group due to ____ decreases: increased shielding and larger AR

First Ionization energy Atomic number The IE trend is actually a little bit crazy, due to the stability of half-filled p orbitals. You don’t need to know the details.

It measures how strongly an atom attracts SHARED electrons. Electronegativity is similar to IE and follows the same general trend as IE

2 Questions, 2 Minutes! Which element has the lowest ionization energy: B, O, or C? Which element has the highest electronegativity: Ba, Mg, or Ca? BORON. Why? MAGNESIUM! Why?

Which of the following has the lowest electronegativity? A. P B. Mg C. Cl D. Na E. Si Which of the following atoms has the highest IE? A. Sb B. P C. As D. Al E. Si

Which one of the following ranks the atoms from smallest to largest radius? A. O, Ca, Zn, Ba B. O, Zn, Ca, Ba C. O, Zn, Ba, Ca D. Ba, Ca, Zn, O

Which of the following is ranked in order of largest to smallest atomic radius? A. Rb>Mn>S>Ge>F B. Rb>Mn>Ge>S>F C. F>S>Ge>Mn>Rb D. Mn>Rb>F>S>Ge E. Rb>Ge>Mn>F>S

Atoms don’t always share their e- equally, so bonds can be: Chemical Bond: force that holds 2 atoms together Ionic Electrons are given away; cations and anions attracted to each other Polar Covalent Electrons are unequally shared one atom “hogs” the electrons more and has a slightly negative charge Nonpolar Covalent Electrons EQUALLY shared between atoms.

What type of bond do Na and N have? Calculate the difference in EN between the two atoms in the bond! (metal/nonmetal) (two nonmetals) 3.0 – 0.9 = >1.7……..ionic bond nonpolar covalent polar covalent ionic

What kind of bond exists between two atoms of chlorine? 3.0 – 3.0 = 0……. NON polar COVALENT *note the even distribution of the electron cloud COVALENT BONDS Single: 2 atoms share 2 e- (1 pair) Double: 2 atoms share 4 e- (2 pairs) Triple: 2 atoms share 6 e- (3 pairs) Cl

What type of bond will form between H and O? 1.4  polar covalent The more EN atom (O) will get the e-’s for a greater amount of time and thus be slightly more negative You may either put lowercase delta negative (δ - ) near the most EN atom in the bond to indicate a slight negative charge, or draw arrows toward the most EN atom, or both δ+δ+ δ-δ-

Why do water molecules stick together? δ – ends of O are attracted to δ+ ends of H, so hydrogen (H) bonds form between molecules Which is stronger, the H bonds or the polar covalent bonds?

Intramolecular forces: Forces that hold atoms together to make a molecule Ex. covalent or ionic bond between 2 atoms Intermolecular forces: (“Van der Waals forces”) Weak forces that attach molecules together Ex. dipole-dipole interactions (H- bonding), London forces