2.5 - 2.7 The Structure of The Atom, Subatomic Particles, &

The Periodic Table

The Structure of the Atom

• Explain Ernest Rutherford’s experiment:– 1.) What was it called?– 2.) Describe it?– 3.) What did Rutherford discovery?

1.) The gold foil experiment.2.) Used a radioactive source that emitted alpha particles at a piece of gold foil. Most went through, but some bounced back at extreme angles.3.) The atom is made up of mostly empty space, but has a small dense positively charged nucleus.

Nuclear Theory

Where is most of the mass of the atom, and why what makes up this mass?– The nucleus, which is made up of protons and neutrons.

What subatomic particle orbits this mass and where are they found?– Electrons, which are found in orbitals.

When an atom is electrically neutral, the atom has as many ? as ? – Protons and electrons

Properties of Subatomic ParticlesParticle Mass (amu) Charge (relative) Symbol

Proton

Neutron

Electron

Particle Mass (amu) Charge (relative) Symbol

Proton 1 +1 p+

Neutron 1 0 n0

Electron 0 -1 e-

Particle Mass (amu) Charge (relative) Symbol

Proton

Neutron

Electron

Identifying an Element

When looking at the periodic table, which number identifies the element? Which subatomic particle does this number represent? What is the symbol of this number?

Atomic number (number of protons), indicated by the symbol Z

A unique one, two or three letter abbreviation of an element is called its…? How is this abbreviation written?

Chemical symbol written so that the first letter is always capitalized, and letters that follow are lowercase.

Isotopes

What is an isotope? Give an example.

An isotope is an atom with the same number of protons, but a different number of electrons.C-12, C-13, and C-14, each have 6 protons, but a different # of neutrons.

How many neutrons does C-14 have, and what does the 14 in C-14 represent?

8 neutrons. The 14 is that isotopes mass number (protons + neutrons). The mass number is symbolized by an A

Ions

What is an ion? Give an example.

An atom that loses or gains electrons. Ca2+ is an example of an ion. What must have happened to calcium for it to have a charge of 2+? Is Ca2+ an anion or cation?

Calcium lost two electrons, and became a cation. Is the size of the calcium ion larger or smaller than the calcium atom? Why?

The calcium ion is smaller than the calcium atom, because the loss of two electrons results in less e- to e- repulsion, bringing the remaining electrons closer to the strong positively charged nucleus.

Let’s Locate The Following on the Periodic Table

• Metals• Non-metals • Metalloids • Groups (or Families)• Periods• Main Group Elements • Transition Elements (Transition Metals)• Halogens • Alkaline Earth Metals • Alkali Metals• Noble Gases

What is periodic law?

Chapter 2 pg. 80 #’s 52, 54, 58, 63, 68, 70 Read: 2.8 – 2.9 pgs. 66-75