Ch. 2 The structure of Matter

The number of electrons in the outermost shell is:

1. Equal to its group in the periodic table 2.Determines the valence of an atom

An alpha particle is a helium nucleus that contains:

2 protons and 2 neutrons

No outer shell can contain more than?

8 electrons

The arrengment of the periodic table of the elements

An arrangment of all know elements into rows and columns. the rows relate to the number of eletron shells present; columns relate to the number of eletrons in the outermost shell.

Describe how ion pairs are formed.

An ion pair is formed when an electron is removed from an atom by ionizing radiation.

List the fundemental particles within an atom.

Electrons, protons and neutrons

Why doesn't an electron spontaneously fly away from the nucleus of an atom?

Electrostatic force of attraction, eletron binding energy.

The numbwer of outermost electron shell is:

Equal to its period in the periodic table.

How does corbon 14 dating determine the age of petrified wood?

Fixed C14 in petrified wood decays, while C14 in living wood is replenished.

The Rutherford atom

the first discription of an atom having a nucleus.

The time required for a qauntity of radioactivity to be reduced to one half its original value is:

Half life of a radioisotope

What is the removal or addition of an orbital eletron form an atom?

Ionization

Atomic nuclei that have the same atomic mass number but different atomic numbers are:

Isobars

What has the same atomic number and the same atomic mass number?

Isomer

Atoms that have the same number of neutrons but different numbers of protones are:

Isotones

Atoms that have the same atomic number but different atomic mass numbers are:

Isotopes

Describe the difference between alpha and beta emmissiion?

Mass and charge on the particle. An alpha particle has four units of mass and two units of positive charge. A beta particale has essentially no mass and one unit of negative charge.

3.3 half lives =

1 tenth life

Photon

Any quantum of electromagnetic radiation. It has no mass and no charge.

The particle of an element is an:

Atom

What is electrically neutral?

Atom

What is essentially empty space?

Atom

What is the smallest particle that has all the properties of an element?

Atom

What force keeps an electron in orbit?

Centripetal Force

Any quantity of one type of molecule is a:

Chemical Compound

What are the fundemental particale of an atom?

Electron, Proton, Neutron

The smallest particle of a compound is a:

Molecule

Atoms of various elements may combine to form structures called:

Molecules

Nucleons

Neutrons and protons

Chemical compound

New substance that is formed when two or more atoms of different elenets combine.

Who developed the concept of the atom as a miniature solar system?

Niels Bohr

Con atoms be ionized by changing the number of positive charges?

No. Positive charges (protons) do not move, they are confined to the nucleus.

The atom mass number and the precise mass of an atom are:

Not Equal

For what is Mendeleev remembered?

Periodic table of elements

Positron

Positively charged beta particle

Emission of particles and energy in order to become stable is:

Radioactivity

Emmision of aplpha particles, beta particles and usually gamma rays is:

Radioactivity Decay

What determines the chemical properties of an element?

The arrangements of electrons in the outermost shells.

What property of an atom does binding energy describe?

The energy required to hols nucleons together as a nucleus (nuclear binding energy). the energy required to maintain eletrons in orbit about the nucleus ( electron binding energy).

Alpha particle

The nucleus of the helium atom - two neutrons and two protons

Radioactive half life

Time required to reduce radioactivity to half its origninal value.

W (chemical symbol for what element)?

Tungten

K shell

innermost electron shell

A beta particle is an electron emitted from the nucleus of a:

radioactive atom.

In their normal state, the electric charge on the atom is?

zero