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Basic Chemistry

Basic Chemistry. An introduction. Vocabulary. elements- single substances that can not be broken down into simpler substances atom- smallest particle of an element that still has all of the properties of that element Ion – an atom with a (+) or (-) charge

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Basic Chemistry

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  1. Basic Chemistry An introduction

  2. Vocabulary • elements- single substances that can not be broken down into simpler substances • atom- smallest particle of an element that still has all of the properties of that element • Ion – an atom with a (+) or (-) charge • symbol- letter or letters representing an element • compound- the chemical combination of two or more elements • molecule- smallest part of a compound which still has all of the properties of that compound

  3. Atoms and Subatomic Structure • Atoms are the basic building blocks of all matter in the universe • Your desk • Your paper • YOU! are made up of atoms • Atoms are made up of 3 subatomic particles: • Protons - carry a positive charge (+) • Neutrons – carry no charge (no charge) • Electrons – carry a negative charge(-) • Protons and Neutrons are found together at the center of the atom in the nucleus

  4. Layout of the atom Nucleus – holds the Protons and Neutrons and is found in the center of the atom. Electron energy levels (shells)– This is the most likely place you would find an electron. - 1st electron shell holds 2 electrons - 2nd electron shell holds 8 electrons - 3rd electron shell holds 8 electrons Valance shell (energy level) – the outer most electron shell of an atom.

  5. Mass of subatomic structures • Protons and neutrons have an almost equal mass of 1 • Electrons are much smaller and lighter and have a mass of approximately 1/1836 of the mass of a proton

  6. Quarks – The makeup of Protons and Neutrons • Protons and Neutrons are made up particles called quarks. • These quarks are held together by other particles called gluons

  7. Atoms and Ions • All atoms are neutral – meaning that however many protons (+) there are there is and equal number of electrons (-) • Ion – is an atom with a charge (when an electron is lost or gained) • When an atom loses an electron (-) it will have a +1 charge • When an atom gains and electron (-) it will have a - 1 charge

  8. Atomic Mass and Atomic Number • Atomic Number – is the number of protons in an element • Atomic Mass – is the number of protons plus the number of neutrons in an element (Mass number) • Number of Neutrons – to find the number of neutrons in an atom subtract the atomic number from the atomic mass. • Each element has a different atomic number (ex – Hydrogen has 1 proton in its nucleus and therefore has an atomic number of 1)

  9. Finding Neutrons, Protons, and Electrons Ex 1. Carbon – Atomic number = 4 Atomic mass = 8 Find Protons, Neutrons, and Electrons P (+) = 4 N = 4 E (-) = 4 Ex 2. Oxygen – Atomic Number = 8 Atomic Mass = 17 P (+) = 8 N = 9 E (-) = 8

  10. Isotopes • Isotopes – an atom that differs only in its number of neutrons in the nucleus. • This does NOT change the element • This only changes the atomic mass • EX. Oxygen has an atomic mass of 16, 17, and 18 • All of these are Oxygen atoms just with a different number of neutrons in the nucleus

  11. Carbon Isotopes

  12. Goal of all Atoms • The goal of all atoms is to have a stable outer energy level. This goal leads to the bonding of atoms. • Bonding can happen two ways. • Sharing of valence electrons • Transfer of valence electrons

  13. Bonding • 2 Types of Bonding • Covalent bonding – when 1 or more electrons are SHARED between atoms • Ex. Water (H2O) – Hydrogen and Oxygen each share 1 electron • Ionic Bonding – when 1 or more electrons are TRANSFERRED between atoms • Ex. Salt (NaCl) – Sodium looses an electron making it a +1 ion and Chlorine gains an electron making it a - 1 ion. Opposites attract and an ionic bond is formed

  14. Examples of Bonding

  15. Chemical and Structural Formulas • Chemical Formula – each element is represented by its chemical symbol and the number of atoms is shown in subscripts. Ex. H2O, CO2, CH4, C6H12O6 • Structural Formula – it show the chemical symbol of each element and how they are bonded to one another.

  16. Structural Formula

  17. Amino Acid Structural Formula

  18. Chemical reactions • Chemical change or chemical reactions – whenever different substances are formed a chemical change or reaction has occurred • Reactants – substance that were present before the chemical reaction • Products – the new substances produced by the chemical reaction

  19. Reactants  Products

  20. Law of Conservation of Mass • Law of Conservation of mass – states that mass can neither be created or destroyed. - Because atoms have mass they cannot be created or destroyed they can only be rearranged.

  21. EX Law of Conservation of Mass

  22. pH Scale • A scale which measures the amount of H+ ions solution. • The greater the H+ ions in a solution has the greater the acidity • The greater the OH – ions in a solutions the greater the Basicity • When H+ ions = OH - ions the solution is neutral and water is formed. (H2O)

  23. pH Scale

  24. Indicators • Benedicts solution (must heat before use) • indicator for glucose, its initial color is blue and the final color (if sugar is present) is orange/red • Lugols Iodine • Indicator for starch, its initial color is amber and the final color (if starch is present) is blue or black • Buirets Solution • Indicator for protein. Its initial color is blue and the final color (If protein is present) is purple • Indicators are used to help us determine is something is an acid or a base • Litmus paper – shows base or acid • pH paper – shows actual pH of acid or base

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