Ch. 2 challenge questions

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.

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

Electrostatic force of attraction, eletron binding energy.

How does carbon 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

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.

Photon

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

What is electrically neutral?

Atom

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

Atom

What force keeps an electron in orbit?

Centripetal Force

What are the fundemental particale of an atom?

Electron, Proton, Neutron

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 elements combine.

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

Niels Bohr

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

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

For what is Mendeleev remembered?

Periodic table of elements

Positron

Positively charged beta particle

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 electrons 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)?

Tungsten

How much more tightly bound are K-shell electrons in Tungsten than (a) L-shell electrons, (b) M-shell electrons, (c) free electrons?

a. 58 keV.b. 67.2 keV.c. 70 keV.

List the fundamental particles within an atom.

electrons, protons, neutrons

K shell

innermost electron shell

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

radioactive atom.