Module 5: Matter

What happens to the number of neutrons as we progress up the periodic table to larger and large atoms

• # of neutrons increases exponetially

• faster than the # of protons

what has no neutrons

• hydrogen

• Z=1

number of neutrons and protons balance normally

helium (Z=2) to chlorine (Z=17)

where do neutrons outnumber protons

Z=18 and above

Z=17 chlroine

element where neutrons start to outnumber the protons

why do the neutrons outnumber the protons

• takes less nuclear energy to hold neutrons together

why does it take less nuclear energy to hold neutrons together

because they do not electrically repel each other like protons do

what is the advantage of having more neutrons than protons

• when combined into very large nucleei it takes less energy to hold nucleus together when neutrons outnumber protons

atomic mass?

# of protons and neutrons

what letter represents atomic mass

A

atomic mass does not equal?

atomic weight

radius of a typicall atom is?

1 A (angstrom) or 10^-8cm

radium of a typical nucleaus?

abt 0.0001 A (angstrom) or 10^-12 cm

1 AMU =?

1/12 the mass of carbon atom

electron mass

• 0.000549 amu

proton mass

1.000759 amu

neutron mass

1.000898 amu

proton neutron and electron mass from smallest to largest

electron, proton, neturon

what is each element deterimed by

# of protons in the nucleus

Z =?

• atomic number

• number of protons

N =?

• number of neutrons

• this can vary

A=?

• mass number

• approximated mass of atom

• number of protons and neutrons together

N + Z =?

A

nuclear shorthand?

• A = mass number

• Z= atomic number

• N = neutorn number

• X = chemical symbol for element

what do we call a variation of an element

nuclide

• over 1500 nuclides known to exist

isotope?

• same # protons

• atoms vary in the number of neutrons they possess even tho Z remains constant

• A and N differ

What is constant in isotope?

Z number

A and N differ

Isobar?

• same mass number (A)

• chemically different elements that have the same mass becuase they contain the same total combined number of neutrons and protons

what is constant in an isobar

• A (mass number)

• Z and N diffent

• example 3He and 3H

Isotone?

• same number of neutrons

what is constand in an isotone?

• N (neutron number)

• A and Z differ

Isomer?

• differ in energy levels

• atoms that are exactly alike but one is an energized transitional state or a different state of stability

• denoted by placing an m beside the A

what is constant in an isomer

A Z and N

what is energized state called

metastable

ground state?

more stable state

what is most important isomer in nuclear medicine

99mTc - technetium

what is this?

isotope

what is this

isobar

what is this

isotone

what is this

isomer

what does the line of stability refer to?

• nucleus configuration prefers an equal number of protons and neutrons until chlorine (17) after which extra neutrons are needed to keep the nucleus from falling apart

radionuclidic purity?

the percentage of that element, in the desired chemical form and of the desired radionuclide