Mrs. “Chemistry is the fun stuff” Burge ATOMS!!!! Mrs. “Chemistry is the fun stuff” Burge

Atoms Atom- the smallest particle of an element that retains the elements properties Remember an element is only made of one kind of atoms Anything made of iron is made only of iron atoms

Parts of an atom An atom is made up of 3 different parts: Protons- +, positively charged particle that remains in the center of the atoms Each proton has a 1+ charge Neutrons- neutral charged, or non charged particles that remain in the center of the atom Electrons- -, negatively charged particles that orbit the atom Each electron has a 1- charge Extremely small, smaller than other 2 particles and do not affect atomic mass

Parts of an atom An atom has 2 different sections: Nucleus- positively charged center of the atom The nucleus contains proton and neutrons Electron Cloud- negatively charged outer area of the atom Electrons orbit the nucleus in this area 100,000 times larger in diameter than the diameter of the nucleus

Quarks Quarks are even smaller particles that make up Protons and Neutrons Electrons are not made up of smaller particles Scientists continue to try and learn more about Quarks everyday They use atom accelerators to cause collisions that break the protons and neutrons apart Their efforts are trying to find new particles and to try and further their explanations for how the universe was formed

Dalton’s Atomic Model Dalton’s Atomic Model consists of 6 parts: Matter is composed of extremely small particles called atoms Atoms are indivisible and indestructible (somewhat) Different atoms combine in simple whole number ratios to form compounds In chemical reactions, atoms are separated, combined or rearranged

Rutherford Gold Experiment Rutherford sent radiation through a piece of gold foil and found that some particles passed through, some were scattered and some bounced back This showed that atoms have empty space and other areas of high concentration of matter

Atomic Number This is DIFFERENT than the Atomic Mass/Mass number This is the number of protons the atom has The protons are what change an atom into a different element Each element can have different number of neutrons and electrons but will always the same number of protons

Mass Number The mass number of an atom is the sum of the number of protons and neutrons in the nucleus of the atom Mass # = #of protons + #of neutrons

Isotopes Isotopes are atoms of the same element (have the same number of protons) but have a different number of neutrons To identify isotopes we put the mass number in the name of element Example: Carbon-12, Carbon-14 (radioactive)

Atomic Mass Atomic mass is the mass of an atom Only protons and neutrons are counted because electrons are too small Protons = 1.67*10-24 Neutrons = 1.67*10-24 Electrons = 9.1*10-28 What do these numbers mean? Atomic mass is contained almost entirely in the nucleus of the atom Measured in unit called (amu) = atomic mass unit

Average Atomic Mass The average atomic mass is the weighted average mass of all the naturally occurring isotopes of an element Takes into account how often each isotope occurs This is why the atomic mass on the periodic table is not a whole number (has decimals)

Elements on the Periodic Table