5.2 Reading Guide

1. The Modern Periodic Table 5.2 Reading Guide

2. 9. How is a keyboard an example of a periodic pattern? • On a keyboard there is a repeating pattern of notes. The scale repeats at regular 8-note intervals.

3. 10. How are elements arranged in the modern periodic table? • In the modern periodic table the elements are arranged by increasing atomic number.

4. 11. Why didn’t Mendeleev arrange the elements like they are in the modern periodic table? • Mendeleev developed his periodic table before the discovery of protons. He didn’t know that each element has a unique number of protons.

5. 12. Please describe what a “period” is on the periodic table. • Each row in the periodic table is called a period.

6. 13. According to the periodic table at the top of page 131, how many elements does period 7 have? • Period 7 has 32elements: • Spaces have been left for those that haven’t been discovered (synthesized)

7. 14. Why does the number of elements per period differ? • The number of elements per period varies because the number of available orbitals increases from energy level to energy level.

8. 15. Please explain what a “group” is on the periodic table. • Each column on the periodic table is called a group.

9. 16. What do elements in the same group have in common? • Elements within a group have similar properties.

10. 17. An element’s electron configuration determines its __________ properties. • Chemical • Chemical properties = reactivity & flammability

11. 18. Please explain the periodic law. • Periodic law refers to a pattern of repeating properties • Members of a group in the periodic table have similar properties.

12. 19. Look at page 132-133. What is the first element in group 2A? • Be = Beryllium

13. 20. What is the definition of an atomic mass unit (amu)? • An amu is defined as one twelth the mass of a carbon-12 atom

14. 21. Please explain what a weighted average is. • In a weighted average some values are more important than other values. • E.g. grades – 60% tests, 25% labs, 15% daily work

15. 22. How are weighted averages related to mass numbers (atomic mass)? • Atomic mass depends on the distribution of an elements isotopes in nature. • Those isotopes that occur in higher numbers naturally are given more “weight” in the average. • E.g. grades – test scores are weighted more heavily than labs

16. 23. What are 3 ways that the periodic table classifies elements? • Metals • Nonmetals • Metalloids

17. 24. What are 3 properties of metals? • Good conductors of electricity and heat • Malleable • Ductile

18. 25. What is one distinctive property of the transition elements? • The transition elements have the ability to form compounds with distinctive colors • E.g. colored glass • E.g. Black Hills gold

19. 26. What are 2 properties of non-metals? • Poor conductors of heat & electricity • Low boiling points so mostly gases at room T • If solid at room T then brittle

20. 27. What are metalloids? • Metalloids are elements with properties that are between those of metals and nonmetals • A metalloids ability to conduct electric current depends on T

21. 28. What happens to elements as you move from left to right across the periodic table? • Across a period from left to right, the elements become less metallic and more nonmetallic in their properties.