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Element Atomic structure of symbol _________( ): ~ Atom ~ Isotope ~ Ion Protons – Neutrons – Electrons – Mass – Charge – Protons – Neutrons – Electrons – Mass – Charge – Protons – Neutrons – Electrons – Mass – Charge – Summary: Elements are made out of atoms. • And there are 3 parts to an atom, or “ Subatomic particles ”. 1. PROTON 2. NEUTRON 3. ELECTRON …………………………………………………………………………………. …………………………………………………………………………………. …………………………………………………………………………………. Protons and Neutrons are found in the center of the atom, called the “Nucleus” The type of Atom is determined by the number of Protons. Proton • Has a positive (+1) charge. • Has a mass of 1 amu (atomic mass unit). • Found in the nucleus of an atom. • The # of protons determines the type of atom (or element). ATOMIC NUMBER: - Is the number of Protons in an atom. - In any Atom the … # of protons = # of electrons = Atomic Number Question: If subatomic particles with in an atom are found in equal amounts then, what is the charge of all Atoms? What are isotopes of Potassium (K)? Neutron • Has a neutral (0) charge. • Has a mass of 1 amu. • Found in the nucleus of an atom. MASS NUMBER: - The sum of the number of protons and neutrons in an atom. Symbolic Notation, for an elements identity includes; 1. Element symbol 2. superscript (left) = Mass # 3. subscript (left) = Atomic # 4. top right corner = charge on ion (a.k.a.~ oxidation #) Isotope: • Same element (same # of protons), but different number of neutrons (different mass #) • Isotope notation = Hydrogen-1.......“protium” Hydrogen-2 .....“deuterium” Hydrogen-3 .......“tritium” Explain the difference between the hydrogen atoms. 3 isotopes of Potassium (K) - Calculating Atomic Mass: Step 1. - Calculate each isotope’s contribution to the atomic mass Mass contribution = (mass)(% abundance) convert % to decimals Step 2 - Add the mass contributions to find the average atomic mass. Atomic Mass = (___ amu) + (___ amu) Electron • Has a negative (-1) charge. • Has no mass. (1/1840 or 9.11X10^-28 grams) • Found in orbit around the nucleus of an atom. - Electrons are found outside the nucleus in an “electron cloud” or “orbitals” or “energy levels”. ~ Actual picture of electrons orbiting a nucleus. ~ digital model of electron orbitals ~ What do Electrons do? - Cause elements to have a positive (+) or negative (-) charge. - Also, cause elements to bond together. Important to remember 1. Atoms are neutral. 2. Ions are atoms with a charge. - Ion: • Is an atom with a charge (+ or -). • A neutral atom (element) has equal #’s of protons & electrons. • All atoms are neutral, and they become an ion by gaining or loosing electrons. - Ion: - Atoms become ions by filling their highest electron energy level. • When the highest electron energy level is full the atom is “STABLE” or Non-reactive. • many elements need 8 valence electrons to become stable. • Valence electrons are the electrons found in the highest energy level (or the farthest orbital from the nucleus).