200 likes | 542 Views
Atoms and the Periodic Table. Atoms and the Periodic Table. We can classify (arrange) elements in different ways:-. naturally occurring/made by scientists. solid/liquid/gas. metal/non-metal. The Periodic Table of the Elements. lists the chemical elements in increasing atomic number
E N D
Atoms and the Periodic Table. We can classify (arrange) elements in different ways:- • naturally occurring/made by scientists • solid/liquid/gas • metal/non-metal
The Periodic Table of the Elements. • lists the chemical elements in increasing atomic number • arranges elements with similar chemical properties in groups (vertical columns). • All the elements in a group have similar chemical properties as they have the same number of outer electrons (valence).
Group 1 - the alkali metals Groups of elements have names: – Between groups 2 and 3 - the transition metals Group 7 - Group 0 - the halogens the noble gases
Every element is made up of very small particles called atoms. • positively charged nucleus • negatively charged electrons outside the nucleus in energy levels.
HELIUM ATOM Shell proton N + - + N - neutron electron
ATOMIC STRUCTURE He 2 Atomic number the number of protons in an atom 4 Atomic mass the number of protons and neutrons in an atom number of electrons = number of protons
Valence Electrons • are the outermost electrons of an atom • important in determining how the atom reacts chemically with other atoms. • Valence electrons= full then the atom won’t bond • Valence electrons not full atom wants to bond
covalent bond/ chemical bonding • A covalent bond =sharing of pairs of electrons between atoms. • single bond= a two electrons shared • double bond =four bonding electrons instead of the usual two.
Lewis Dot Structures • Shows valence electrons • Each Atom wants 8 electrons= happy element☺
Single Bond • single bond= a two electrons shared
Double Bond • double bond =four bonding electrons instead of the usual two.
Important Stuff to know!!! • Hydrogen on needs two valence electrons to be happy and fill • C can make 4 bonds • O can make two bonds • N can make three bonds • H can make one bond
Lets Practice • Flip to the back of your notes • How many valence electrons for each ( hint Group number) • Draw Lewis dot for H, O, H • Lets bond!!!
Lets do another one • How many valence electrons for each ( hint Group number) • Draw Lewis dot structure for O , O, C • Lets bond!!!
Your Turn with Fruit Loops • H and H • C and H ( hint four of them) • N and H ( hint three of them)
More fun with fruit loops • H2O • NOH3 • CO2 • NH3