The Periodic Table

1. Group (family / column) The Periodic Table Period (row)

2. Review • Period • Row of elements. • All elements in a period share the same number of energy shells. • Group • A column of elements. • All elements in a group share the same number of valence electrons. They also share characteristics • What is Group 1’s family name? • What chemical property do they all share?

3. Classes of Elements in the Periodic Table metal Non metal • Most elements are classified as either a ______________ or a _____ ___________. • Where are these two types generally found? • Why is an elements group or position important? • The position of an element, relative to other elements in the periodic table, provides a way to predict the physical and chemical properties of the element.

4. REVIEW Basic Trends in the Periodic Table • As you look across a period or down a group, several properties of elements change in a regular way. • Elements are organized by… • Every period has… • Every group or family has…

5. NAME the Element

7. Higher level trendsReactivity and Atom Size ALL Periodic Table Trends are Influenced by three main factors:

8. Discuss in groups Which two families are most reactive? Why might they be so reactive? Why are some elements more/less reactive than other elements? Explain

9. # of Valence Electrons • Degree to which the valence shell is full or stable •  Think Full House is happy • Energy Level • Higher energy levels are further away from the nucleus. •  Think Distance • Charge on nucleus (# protons) • More charge pulls electrons in closer. • (+ and – attract each other). •  Think Greater Electromagnetic force

10. What do they influence? • Energy levels have an effect on the GROUP ( FAMILY ) • Nuclear charge has an effect on a PERIOD

11. 1) Reactivity and the Outermost Electrons • Many of the properties of elements are determined by the ________________ of the ______________ in the ________________ occupied energy level. • REVIEW: The electrons in the outermost occupied energy level of an atom are called _______ __________. electrons arrangement outermost Valenceelectrons

12. 1) Reactivity and the Outermost Electrons Family or Group • Atoms within the same _______________ in the periodic table have the same number of ________________ in their outer energy level. • Therefore, elements in a __________ (vertical column or stack) tend to react in a ______________ way. electrons group similar

13. 2.) Reactivity and Atom Size outermost nucleus • The distance from the centre of the _______________ to the _______________ ________________ determines the _______ of an atom. • Atoms that need to _______ 1 electron or loose _ electron are _______ reactive. • Which two families are most reactive? Why? electrons size gain 1 most

14. Atomic Size } Atomic Radius • this is half the distance between the two nuclei of a diatomic molecule or • the distance from the nuclei to the valence shell Radius

15. Atomic Size - Group trends H • As we increase the atomic number (or go down a group). . . • each atom has another energy level, • so the atoms get bigger. Li Na K Rb

16. down farther • As you move ________ a group (family - column), there are more shells or energy levels, so the valence electrons are ___________ from the nucleus, and the atom is therefore _________ in size. • The farther the valence electron is from the nucleus in metals, the ___________ it is lost, and therefore is _______ reactive. • This is because of the electromagnetic attraction with the positive nucleus being smaller larger easier more

18. Remember the Electron has a NEG. charge (-) and the nucleus has a POS. (+) charge. • The greater the distance btw the – and the + regions, the weaker the nucleus’ (+) hold of the electron (-) is. • REVIEW: As you move across a period (row) to the _________, atoms gain an additional electron. right

19. Atomic Size - Period Trends • Going from left to right across a period, the size getssmaller. • Electrons are in the same energy level. • But, there is more nuclear charge (# of protons) • Outermost electrons are pulled closer. Na Mg Al Si P S Cl Ar

22. “Halogens” • _____________ or group 17 elements are diatomic, meaning they are found in pairs. • The positive nucleus repel one another, so the closer the nucleus are to one another the easier it is to separate them (so that they can form an ionic bond). • The easier they separate the more ____________ they are. As you move down the group the distance between nucleus’s increases and additional shells form in-between them, helping to shield the nucleus from one another and decreasing how much they repel one another (making it harder to break them apart). reactive

25. Isotopes • Even though atoms may not be identical (remember: atomic mass was an average of all the variations),they are both atoms of the same ____________ if they have the same number of ____________. • Isotope: one of two or more forms of an element that have the _______ number of __________ but a __________ number of _____________. • “An element whose atomic mass has changed.” element protons same protons neutrons different

26. Atomic Mass and Isotopes • While most atoms have the same number of protons and neutrons (or close to), some don’t. • Some atoms have more or less neutrons than protons. These are called isotopes. • An atomic mass number with a decimal is the total of the number of protons plus the average number of neutrons.