What is chemistry?

Chemistry is the study of the nature and behavior or matter.

Define an Atom.

What are the three subatomic particles

that atoms consist of?

1. Protons

2. Neutrons

3. Electrons

What is Dalton's Atomic theory?

• All elements are composed of atoms. All atoms of a given element are identical in size, mass, & chemical properties. The atoms of one element are different from atoms of all other elements.
• All compounds are composed of atoms with more than one element. For any given compound, the ratio of the numbers of atoms of any two of the elements present is either an integer or a simple fraction.
• A given chemical reaction involves only the separation, combination or rearrangement of atoms; it does NOT result in the creation or destruction.

Name the characteristics of a proton.

• Protons carry a positive charge
• 1 proton = 1 atomic mass unit (AMU or u) = 1 dalton (Da)
• the Atomic number (Z) of an element is equal to the number of protons of that element.
• Positively charged particles carry the same QUANTITY of charge as an electron, but have a mass that is ~1,840x greater than an e-.
• Mass of nucleus of an atom comprises of entire weight of an atom, it only occupies 10^-13 of the volume of the atom.

What are the characteristics of a neutron?

• Neutrons have no charge
• Have a mass that is slightly larger than that of a proton = ~1 u
• Different isotopes of one element have different number of neutrons but the same number of protons.

What are electrons?

• Electrons carry a negative charge.
• Electrons mass is 1/1,837 the mass of a proton or neutron

What are valence electrons?

• Valence electrons are the electrons on the outer most shell of an atom.
• the furthest from the nucleus, the weaker the attractive force of the positively charged nucleus and the more likely the valence electrons are influenced by other atoms.

What is considered a neutral atom?

• Neutral atom have the same number of electrons as protons.

How is the atomic number determined?

The number of electrons in a neutral atom. 

What does a positive or negative charge an atom indicate?

• An Ion is a result of a positive or negative charge on an atom.
• a + is a loss of an electron
• a - indicated the gain of an electron

Determine the number of protons, neutrons and electrons in a Nickle-58 atom and in a nickel-60^2+ atom.

• Nickel has an atomic number of 28 & mass number of 58.
• NI-58 has 28 Electrons, 28 protons and 30 Neutrons (58-28=30)
• nickle-60^2+ has 26 electrons, 28 protons, 32 neutrons (30+2 neutrons = 32)

How is the atomic mass number (A) found?

How is AZX written for an atom?

Atomic Mass number (A) is the sum of nucleons (protons + neutrons)

A superscript, Z subscript before X is written to show.

A= Atomic Mass number

Z= Atomic number

X= atom

What is the molecular weight?

The Molecular weight is the weight in grams per one mole (mol) of a given element (g/mol).

What is a mole?

A mole is a unit used to count particles and is represented by Avogadro's number 6.02 X10^23 particles/mol.

What does Avogadro's number represent?

 Avogadro's number is determined by how many atoms of carbon are in 12.0 g of carbon-12.

Are isotopes with same number of electrons and protons

similar or different in chemical properties?

Isotopes with the same number of electrons and protons are similar in chemical properties.

What is the mass of one atom of nitrogen with 14 u in grams?

14 g

What is an isotope?

An isotope is an atom that has the same number of protons (same atomic number, z) but has different number of neutrons.

Describe how many protons and neutrons are found in

1) Carbon-12

2) Carbon-14

1) Carbon 12, 6 p+ and 6 n

2) Carbon 14, 6 p+ and 8 n

What proportions exist of an element that has two or more isotopes in a collection?

The isotopes are usually present in the same proportions in any same of any naturally occurring element

What is the standard atomic weight?

A weighted average of all the isotopes of an element found naturally on Earth. Found on the table of elements.

Element Q consists of 3 types of isotopes, A, B & C.

Isotope A has an atomic mass of 40 u & accounts for 60% of naturally occurring Q.

Atomic mass of Isotope B is 44 u and accounts for 25% of Q.

Finally, Isotope C has an atomic mass of 4 u and a natural abundance of 15%

What is the atomic weight of element Q?

40 u (.6) + 44 u(.25) + 4 u(.15)

= 24 u + 11 u + 6.15 u

= 41.15 u

Who and when conducted an experiment that showed that the atom has a dense charged nucleus that only accounted for a small proportion of the volume?

Ernest Rutherford in 1911

Who developed the quantum theory?

What is the Quantum theory?

Quantum theory proposes that energy emitted as electromagnetic radiation from matter comes in discrete bundles called quanta.

What is the equation that gives the

energy value of a quantum?

E= hf

h is a proportionality constant = Planck's Constant

Planck's constant = 6.626 x 10^-34 J s

f (sometimes designated as v) is the frequency of the radiation.