RADT 1085 Chapter 2

An electron emitted from the nucleus during some kinds of radioactive decay is known as:

beta particle

Figure 2-1 shows the following approximate sizes: an atom is 10^-10 and Earth is 10^7. By how many orders of magnitude do these objects differ

17

90/38 Sr has a half life of 29 years. If 10 MBq were present in 1950, how much would remain in 2010?

2.5 MBq

If atoms large enough to have electrons in the T shell existed, what would be the maximum number allowed in that shell if V is the most outer shell?

200 electrons

How much more tightly bound are K-shell electrons in tungsten than L- shell, M-shell, and free electrons

58 keV 67.2 keV 70 keV

No outer shell can contain more than _____ electrons.

8

Using the data in Table 2-1, determine the mass of 99Tc in atomic mass units and in kilograms

99 amu, 1.64 x 10^-25

The arrangement of the periodic table of elements

An arrangement of all known elements into rows and columns

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, electron binding energy

Radioactive decay results in

Emission of alpha particles, beta particles, and gamma rays

The time required for a quantity of radioactivity to be reduced to one half its original value

Half life of a radioisotope

K shell

Innermost electron shell

What is the removal of an orbital electron from an atom

Ionization

What has the same atomic number and same atomic mass number

Isomer

Atoms that have the same number of neutrons but different number of protons are

Isotones

Diagram the expected electron configurations of Ca

K-2 L-8 M-8 N-2

Describe the difference between alpha and beta emission

Mass and charge on particle

Alpha particle

the nucleus of a helium atom, consisting of two protons and two neutrons, which is emitted during alpha decay

Photon

Any quantum of electromagnetic radiation, no mass and no charge

The force that keeps an electron in orbit is called what?

Centripetal force

Any quantity of one type of molecules

Chemical compound

Into how many groups are all elements arranged

Eight

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

How many protons, neutrons, electrons, and nucleons are found in the following: 17/8 O 27/13 Al 60/27 Co 226/88 Ra

O- 8,9,8,17 Al- 13,14,13,27 Co- 27,33,27,60 Ra- 88,138,88, 226

The spontaneous emission of particles and energy in order to become stable

Radioactivity

What determines the chemical properties of an element

The arrangement of electrons in outermost shell

What is essentially empty space

The atom

What property of an atom does binding energy describe

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

Rutherford atom

The first description of an atom having a nucleus

radioactive half-life

Time required to reduce radioactivity to half its original value

W is the chemical symbol for

Tungsten

chemical compound

a new substance that forms when atoms of two or more elements react with one another

A helium nucleus with two protons and two neutrons is called a(n) ____.

alpha particle

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

atom

The smallest particle of an element is

atoms

Where do x-rays come from?

electron cloud

List the fundamental particles within an atom.

electrons, protons, neutrons

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

isobars

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

isotopes

The smallest particle of a compound is

molecule

atoms of various elements may combine to form structures called

molecules

In their normal state, atoms are electrically...

neutral

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

not equal

Where do gamma rays come from?

nucleus

For what is Mendeleev remembered?

periodic table of elements

Positron

positively charged beta particle

What are the fundamental particles of an atom

proton, electron, neutron

Nucleons

protons and neutrons