Review of Atomic Structure and Periodic Trends

CHEM 102 - CHP 02

Who proposed the Marble Model of the atom?

John Dalton (1803)

Who proposed the Plum Pudding Model?

J. J. Thompson (1904)

Who proposed the Nuclear Model?

Ernest Rutherford (1911)

Who proposed the Planetary Model?

Neils Bohr (1913)

Who proposed the Electron Cloud Model?

Erwin Schrodinger

How are atoms observed?

With a Scanning Tunneling Microscope (STM)

When does “tunneling” occur in STM?

Current flows when there is a distance < 10^-9m between a needle and a metal object.

How are atoms manipulated?

Can modify the current to make the atoms stick to the needle and drop it elsewhere.

What does the symbol ‘Z’ represent?

atomic number - number of protons (DOES NOT CHANGE)

What does the symbol ‘A’ represent?

mass number - number of protons + neutrons

What are isotopes?

atoms of the same element with the same atomic number but different mass numbers.

Vertical columns of the periodic table are called:

Groups

Horizontal rows of the periodic table are called:

Periods

Group 1 consists of:

alkali metals

Group 2 consists of:

alkali earth metals

Group 3-12 consists of:

transition metals

Group 17 consists of:

halogens

Group 18 consists of:

noble gases

Which halogen is liquid at room conditions?

bromine (Br2)

Which halogen is solid at room conditions?

Iodine (I2)

Why did Bohr’s model fail?

It did not account for electron-electron repulsion

Which element is an ionic anomaly?

Hydrogen - it can either lose or gain an electron to form a cation (proton) or anion (hydride)

Why can transition metals form ions with multiple charges?

Both ns and (n–1)d electrons are available for bonding, leading to variable oxidation states.

Which transition metals form only one charge?

Ag⁺, Zn²⁺, Cd²⁺