friday october 26 th

Friday October 26th

Name the part of the atom.

Test Review

• 1. What was Dalton’s concept of the model of the atom (4 parts) – Matter is made up of atoms– Atoms cannot be divided into smaller pieces– All the atoms of an element are exactly alike– Different elements are made of different atoms

List the particles of an atom

• A. protrons, neutrons and electrons• B. protons are positive– Neutrons are electrically neutral– Electrons are negative

3. What is the electron cloud?

• The electron cloud is the region surrounding the nucleus. This is where the electrons travel.

4. Compare isotopes

and atoms

Both have to deal with the number of protons

and electrons

Stable atoms have the same amount of

neutrons as they do protons.

Isotopes have a different number of neutrons

than protons. The more neutrons the more

UNSTABLE the atom becomes.

5. Which groups are known as the transition elements?

• Groups 3-12 are transitions

• The lanthanides and actinides (located at the bottom of the table) are known as the inner transition elements.

6. Which groups are known as the representative elements?

• Groups 1,2 13-18 are representative elements.

7. Where are the inner transition elements located?

• They are located at the bottom of the periodic table, they are known as the lanthanides and the actinides.

How are the periods different from the groups?

periods

Rows 1-7

Properties that change gradually and predictably as you go

across the table

Groups/families

Groups 1-18 Columns

They are groups of elements that have

similar chemical and physical properties

9. The atomic number is

• The number of protons of an element. • It can also be the number of neutrons of a

stable element.

10. Why are the actinides and lanthanides at the bottom of the periodic table?

• They are at the bottom to save space.

11. Where are the metals located on the periodic table?

• The metals are located to the left of the metalloids.

• To the left of the diagonals.

12.Where are the nonmetals located on the periodic table?

• Non metals are located to the right of the diagonal (metalloids) except for Hg which is located in group 12.

13. Where are the metalloids located on the periodic table?

• Metalloids are located along the diagonal on the periodic table.

14. What type of information is in the element box?

• Name• Atomic number• Atomic mass• Chemical symbol

15. For each group on the periodic table list:

• A. family members• B. name of the group/family• C. what is special about each group?• D. how many valence electrons do each group

have?• E. common uses for each group: list the

element and use for it

16. Which of the three elements are known as the iron triad?

• Iron Fe• Cobalt Co• Nickel Ni

17. In a chemical reaction a catalyst

• Speeds up a reaction

• 18> Which elements can be used as catalyst? – Nickel, zinc, cobalt, ruthenium, rhodium,

palladium, – Platinum group

19. What are synthetic elements?

• Man made. Made in laboratories and nuclear reactions.

20. What type of material is used for dental work?

• Nickel and titanium

21. Why is the periodic table arranged the way it is?

• The atoms are arranged by their atomic number.

• As you go across the rows the properties change gradually and predictably.

• As you look down a column the families/groups have similar physical and chemical properties.

22. If an element is malleable it is

• Bendable. Stretchable

23. If the element conducts electricity well it is a

• Metal

24. What are the energy levels in an atom?

• The different areas for an electron to travel • Each level represents a different amount of

energy

25. What is a molecule?

• A neutral particle formed when atoms share electrons

26.What is a chemical formula? A skeleton equation, and a word equation

• Chemical formula: combination of chemical symbols and numbers that indicates which element and how many atoms of each element are present in a molecule.

• A skeletal equation shows just the numbers and chemical symbols

• A word equation is written in words

28. How does a synthesis reaction differ from a decomposition reaction?

• A synthesis reactions is the opposite of a decomposition reaction. A synthesis reaction puts together

• A decomposition breaks down

30. How can you use your five senses to detect a chemical reaction?

• Sight: when you see a firefly light up• Taste: when you taste spoilt milk• Smell/ touch: billowing clouds of acrid smoke

and waves of intense heat (burning forest)• Hearing: signal flare, fizzing(bubbles being

released)

31. What is the difference between a chemical change and a physical change.

• A chemical change: cannot be changed back to the original reactants

• A physical change: just changes the appearance the original reactants are still the same.

32. Give examples of products and reactants.

• Reactants-are the substances that exist before a reaction happens.

• Product-is the result of the reaction.

• Reactants: cream, sugar, butter, marshmallow cream, chocolate chips

• Result: fudge

33. Do all reactions require activation energy? Explain

• YES< activation is the minimum amount of energy needed to start a reaction.

34./35 How can the rate of a reaction be changed?

• Temperature: you can slow rippening fruit by putting them in a refrigerator. (green tomatoes)

• Increase the temperature will make foods cook faster.

34/35

• Concentration: the closer reactant atoms and molecules are to each other, the grater the chance they will collide and between them and the faster the reaction rate.

• Concentration: is the amount of a substace present in a given volume

34/35

• Surface area: the exposed surface area of reactant particles.

• Which is better to start a fire? A large log or small twigs?

• Small twigs WHY?

36. How does an inhibitor slow a reaction?

• A substance that slows a reaction down.• An inhibitor makes the formation of certain

amounts of product take longer. • Cereal: BHT or butylated hydrxytolune—

increases shelf life and slows the spoiling

37. What are enzymes?

• Are a catalyst• Are large protein molecules that speed up

reactions needed for your cells to work properly.

38. How is heat energy transferred across particles in a reaction?

• Think about going outside… particle movement

39. How is matter conserved in a chemical reaction?

• This will be answered in class… on Friday.