C2 – Chemistry The Atom, Particles and Bonding

C2 – Chemistry - AIMS to represent the electronic structure of the first twenty elements of the periodic table to represent the electronic structure of the ions in sodium chloride, magnesium oxide and calcium chloride to represent the covalent bonds in molecules such as water, ammonia, hydrogen, hydrogen chloride, chlorine, methane and oxygen and in giant structures such as diamond and silicon dioxide

The Periodic Table Columns = groups Group number = number of electrons in outer shell Rows = periods Row number = number of shells

The Electronic Structure of Sodium The Electronic Structure of a Sodium Ion EXAMPLES!!

Covalent Bonding in Ammonia OR

Atoms have a small central nucleus made up of protons and neutrons around which there are electrons In an atom, the number of electrons is equal to the number of protons in the nucleus. Atoms have no overall electrical charge All atoms of a particular element have the same number of protons. Atoms of different elements have different numbers of protons. The number of protons in an atom is called its atomic number (proton number). Atoms are arranged in the modern periodic table in order of their atomic number (proton number). The structure of the atom

11/06/2016 The structure of the atom ELECTRON – negative, mass nearly nothing PROTON – positive, same mass as neutron (“1”) NEUTRON – neutral, same mass as proton (“1”)

The structure of the atom ParticleRelative MassRelative Charge Proton11 Neutron10 Electron0 MASS NUMBER = number of protons + number of neutrons PROTON NUMBER = number of protons

Electronic Arrangement Electrons occupy particular energy levels. Each electron in an atom is at a particular energy level (in a particular shell). The electrons in an atom occupy the lowest available energy levels (innermost available shells) Elements in the same group in the periodic table have the same number of electrons in the highest energy levels (outer electrons)

Which Elements do these Electronic Arrangements represent?! A B C Electronic Arrangement

Electronic arrangements No.ElementShell Hydrogen1 2Helium2 3Lithium21 4Berylium22 5Boron23 6Carbon24 7Nitrogen25 8Oxygen26 9Fluorine27 10Neon28 No.ElementShell Sodium281 12Magnesium282 13Aluminium283 14Silicon284 15Phosphorus285 16Sulphur286 17Chlorine287 18Argon288 19Potassium Calcium2882

Compounds & Bonding Compounds are substances in which atoms of two, or more, elements are not just mixed together, but chemically combined. Chemical bonding involves either transferring or sharing electrons in the highest occupied energy levels (shells) of atoms. COVALENT BONDING!! (Sharing Electrons) When atoms share pairs of electrons, they form covalent bonds. These bonds between atoms are strong. Some covalently bonded substances consist of simple molecules such as H 2, Cl 2, O 2, HCl, H 2 O and CH 4. Others have giant covalent structures (macromolecules), such as diamond and silicon dioxide. Draw out the Covalent Bond Diagrams for all the simple molecules above

Examples of Covalent Bonding Water – H 2 O Methane – CH 4

Ionic Bonding When atoms form chemical bonds by transferring electrons, they form ions. Atoms that lose electrons become positively charged ions. Atoms that gain electrons become negatively charged ions. Ions have the electronic structure of a noble gas (Group 0). Draw the Electronic Arrangement of sodium chloride, magnesium oxide and calcium chloride ions An ionic compound is a giant structure of ions. Ionic compounds are held together by strong forces of attraction between oppositely charged ions. These forces act in all directions in the lattice and this is called ionic bonding.

Ionic Bonding The elements in Group 1 of the periodic table, the alkali metals, have similar chemical properties. They all react with non-metal elements to form ionic compounds in which the metal ion has a single positive charge The elements in Group 7 of the periodic table, the halogens, have similar chemical properties. They react with the alkali metals to form ionic compounds in which the halide ions have a single negative charge

Electronic arrangement Group 1 metals (aka alkali metals) - Have 1 electron in outer most shell - Soft metals, easily cut - Reacts with water and oxygen - Reactivity increases down the group - Low melting and boiling points

Examples of Ionic Bonding Magnesium Chloride

Atomic number Symbol of atom Electronic structure of atom IonElectronic structure of ion 8O[2, 8] , 8, 8, 1K+K+ 17ClCl - 202, 8, 8, 2 Copy and complete the following table

Atomic number Symbol of atom Electronic structure of atom IonElectronic structure of ion 8O2, 6O 2- [2, 8] 2- 19K2, 8, 8, 1K+K+ [2, 8, 8] + 17Cl2, 8, 7Cl - [2, 8, 8] - 20Ca2, 8, 8, 2Ca 2+ [2, 8, 8] 2+ Did you get it all right?