CHEMISTRY December 9, 2014 PERIODIC TRENDS

SCIENCE STARTER Do the Science Starter You have 3 minutes to complete the task You are silent and seated

QUESTION 1 FLUORINE – PERIOD – GROUP – GROUP NAME – ATOMIC NUMBER – VALENCE ELECTRONS – # OF ENERGY LEVELS

QUESTION 2 WHAT IS THE GROUP NAME FOR GROUP 1?

QUESTION 3 WHAT IS THE NAME OF THE ELEMENT LOCATED AT PERIOD 5 GROUP 17?

ATOMIC RADIUS - period You may work with a partner to do the first 3 questions. You may refer to Table S and Periodic Table to help you You have 2 minutes to answer Questions 1-3

PART 1 Q1-3 Symb ol Atomic Number Atomic Radius Li3130. pm Be499 pm B584 pm C675 pm Q1: Q2: Q3:

ATOMIC RADIUS DEFINITION Atomic Radius is an ESTIMATE of the size of the atom or the distance from the NUCLEUS to the edge of the atom.

PART 1 Q5 Going across a period, electrons are added to the outermost energy level. At the same time protons are being added to the nucleus. As a result, the increased concentration of protons in the nucleus creates a higher effective nuclear charge. Thus, a stronger force of attraction pulls the electrons closer to the nucleus resulting in a smaller atomic radius.

ATOMIC RADIUS - Group You may work with a partner to do questions 6-8 You may refer to Table S and Periodic Table to help you You have 2 minutes to answer Questions 6-8

Symb olAtomic NumberAtomic Radius Li3130. pm Na11160 pm K19200 pm Rb37215 pm Q1 Q2 Q3

QUESTIONS 8 Going down a group, the number of energy levels increases. Each subsequent energy level is further from the nucleus. Thus, the atomic radius increases as the group and energy levels increase.

FIRST IONIZATION ENERGY - Period You may work with a partner to do questions 1-2 You may refer to Table S and Periodic Table to help you You have 1 minute to answer Questions 1-2

Q1 Q2 Q3 Sym bol Atomic Number First Ionization Energy Li3520. kJ/mol Be4900. kJ/mol B5801 kJ/mol C61086 kJ/mol

QUESTION 3 First Ionization Energy is the energy required to remove the most loosely bound (outermost) electrons from an atom

QUESTION 4 Going across a period, the atomic radius decreases making the atom smaller thereby making the outer electrons (or valence electrons) closer to the nucleus and more strongly attracted to the center. Therefore, it becomes more difficult to remove the outermost electron

FIRST IONIZATION ENERGY - GROUP You may work with a partner to do questions 1-3 You may refer to Table S and Periodic Table to help you You have 2minutes to answer Questions 1-3

Q1 Q2 Q3 Sym bol Atomic Number First Ionization Energy Li kJ/mol Na11496 kJ/mol K19419 kJ/mol Rb37403 kJ/mol

QUESTION 4 Going down a group, the number of energy levels increases. Thus, the valence electrons are further away from the nucleus making it easier to remove the valence electrons.

ELECTRONEGATIVITY- period You may work with a partner to do questions 5-6 You may refer to Table S and Periodic Table to help you You have 2minutes to answer Questions 5-6

Q5 Q6 Sym bol Atomic Number Electronegativ ity Li31.0 Be41.6 B52.0 C62.6

QUESTION 7 Electronegativity measures an atom’s tendency to attract and form bonds with ELECTRONS

QUESTION 8 Going across a period, the number of valence electrons increases thus, making the electronegativity increasesas the atomic number increases.

ELECTRONEGATIVITY-groups You may work with a partner to do questions 5-6 You may refer to Table S and Periodic Table to help you You have 2minutes to answer Questions 5-6

Q5 Q6 Symb ol Atomic NumberElectronegativity Li3 1.0 Na110.9 K190.8 Rb370.8

QUESTION 7 Based on the table above, as the atomic number increases, the number of energy levels increases. Thus, the valence electrons are located FURTHER away from the nucleus. As a result, the ELECTRONEGATIVITY DECREASES

QUESTION 8 Going down a group, the number of energy levels increases. Thus, the valence electrons are further away from the nucleus resulting in a decreased electronegativity.

METALLIC – Q1 Metallic characteristic of an element refers to how readily an atom can LOSE an electron.

METALLIC – Q2 Going across a period from right to left, the metallic characteristic INCREASES because the attraction between the valence electrons and the nucleus is WEAKER. (MAKING IT EASIER TO LOSE THE ELECTRONS)

PRACTICE ComparisonAtomic RadiusFirst Ionization EnergyElectronegativityMetallic Na to Al Ca to Ba Ga to Br B to Ga Cs to At

WRITTEN ASSIGNMENT IN A CHEMICAL REACTION, WHICH ELEMENT (K OR Br) loses its valence electron first? – State a claim, provide evidence from the periodic table and/or Table S and explain your evidence.