The Periodic Table

1. The Periodic Table Now that we know where (or approximately 
where) to find the parts of atoms, we can 
start to understand how these factors all 
come together to affect how we view the 
elements. We can look at them as individual yet 
interacting chemicals, and we are able to 
group them based, not only on the 
properties they present when in isolation, 
but also the properties they reveal when 
exposed to other elements or compounds.

2. History of the Periodic Table Dmitri Mendeleev, building on the ideas from chemists before him, developed the 
modern periodic table. He argued that element properties are 
periodic functions of their atomic weights. 
We now know that element properties are 
periodic functions of their atomic number. 
By elemental properties, we are describing 
both physical and chemical properties. Atoms are listed on the periodic table in rows, based on 
number of protons.

3. Information on the Periodic Table A periodic table usually has the following information: Name of Atom Element Symbol - the one or two letters 
designating the atom Atomic Number - the number of protons in that particular atom Atomic Mass - the average atomic mass for that atom NOTE: A periodic table may have more information or less information, depending on the publisher and intended use.

4. Periodic Table The periodic table is made of rows and columns: Rows in the periodic table are called Periods. Columns in the periodic table are called Groups. Groups are sometimes referred to as Families, but "groups" is more traditional.

5. groups 1 2 3 periods 4 5 * 6 7 ** * 6 ** 7

6. Periodic Table The periodic table is "periodic" because of certain trends that are 
seen in the elements. Properties of elements are functions of their atomic number. Elements from the same group have similar physical and 
chemical properties. Atoms are listed on the periodic table in rows, based on number 
of protons, which is equal to the number of electrons in a neutral 
atom.

7. [] 1 What is the atomic number for the element in 
period 3, group 16?

8. 2 What is the atomic number for the element 
in period 5, group 3?

9. Special Groups Some groups have distinctive properties 
and are given special names. Alkaline Earth Metals Noble Gases Chalcogens Halogens Transition Metals Alkali Metals

10. Groups of Elements Enjoy Tom Lehrer's Famous Element Song!

11. Group 1 Alkali Metals  (very reactive metals) Alkali Metals

12. Group 2 Alkaline Earth Metals (reactive metals) Alkaline Earth Metals

13. Groups 3 - 12 Transition Metals (low reactivity, typical metals) Transition Metals

14.  Group 16 Chalcogens  (elements of fire) Chalcogens

15.  Group 17 Halogens  (highly reactive, nonmetals) Halogens

16.  Group 18 Noble Gases (nearly inert) Noble Gases

17. Alkaline Earth Metals Noble Gases Chalcogens Halogens Transition Metals Alkali Metals

18. Metals, Nonmetals, and Metalloids The periodic table can be also divided into metals (blue) 
and nonmetals (yellow) . A few elements retain some of 
the properties of metals and nonmetals, they are called 
metalloids (pink). B metals nonmetals Si Ge As metalloids Sb Te ?

19. Diatomic Elements Seven elements in the periodic table are always diatomic. In elemental form, they are always seen as two atoms 
bonded together. H2, O2, N2, Cl2, Br2, I2, F2 H O N F Cl Br I

20. Electron Configuration Since the families are 
based on reactivates, 
and next, how something 
reacts is based off of 
how its electrons are 
arranged. . . Alkaline Earth Metals Noble Gases Chalcogens Halogens Transition Metals Alkali Metals . . . we now know that elements in the same family have very similar electron configurations

21. Group names Noble Gases - Group 18, s2p6 ending Have a full outermost shell Halogens - Group 17, s2p5 ending Highly reactive, need one electron to have a full outer shell. Alkali Metals - Group 1, s1 ending Very reactive Alkaline Earth Metals - Group 2, s2 ending Reactive Transition Metals (d-block) - Groups 3 - 12 somewhat reactive, typical metals, ns2, (n-1)d ending Inner transition metals ( f -block) - the bottom two rows somewhat reactive and radioactive, ns2, (n-2)f ending

22.  3 The elements in the periodic table that 
have completely filled shells or subshells 
are referred to as: A noble gases. B halogens. C alkali metals. D transition elements. E I don't know how to answer this.

23.  4 The elements in the periodic table which lack 
one electron from a filled shell are referred to 
as: A noble gases. B halogens. C alkali metals. D transition elements. E I don't know how to answer this.

24.  5 The elements in the periodic table which 
have a single outer s electron are referred 
to as: A noble gases. B halogens. C alkali metals. D transition elements. E I don't know how to answer this.

25. Looking back at the Periodic Table of 
the Elements Atoms with the same number of electrons in their outer shells or 
same outer electron configuration, have similar chemical behavior. 
They appear in the same column of the periodic table. The periodic table of elements can be grouped into blocks based 
on electron configuration of the atoms. s, p, d, and f blocks will 
have the last electron in the atom filling into these sub shells 
respectively. The elements with configuration - full or half full in their outer sub 
shell are the most distinctive.

26. Stability When the elements were studied it was notices that some of them do 
not react in certain situations in which others do. These elements were 
labeled "stable" because they did not change easily. When these stable 
elements were grouped together, it was noticed that periodically, there 
were patterns in the occurrence of stable elements. Today we recognize that this difference in stability is due to electron 
configurations.

27. Group Numbers 1A 2A 8A 1 2 18 3A 4A 5A 6A 7A 13 14 15 16 17 } 8B 3B 4B 5B 6B 7B 1B 2B 3 4 5 6 7 8 9 10 11 12 There are two methods for labeling the groups, the older 
method shown in black on the top and the newer method 
shown in blue on the bottom.

28. Stability Elements of varying stability fall into one of 3 categories. The most 
stable atoms have completely full energy levels.   ~Full Energy Level  ~Full Sublevel (s, p, d, f)  ~Half Full Sublevel ( d5, f7) 1 2 3 4 5 6 7 6 7

29. Stability Next in order of stability are elements with full sublevels.   ~Full Energy Level  ~Full Sublevel (s, p, d, f)  ~Half Full Sublevel ( d5, f7) 1 2 3 4 5 6 7 6 7

30. Stability Finally, the elements with half full sublevels are also stable, but not as 
stable as elements with fully energy levels or sublevels.   ~Full Energy Level  ~Full Sublevel (s, p, d, f)  ~Half Full Sublevel ( d5, f7) 1 2 3 4 5 6 7 6 7

31. Electron Configuration Exceptions You should know the basic exceptions in the d- and f-sublevels. 
These fall in the circled areas on the table below. 1 2 3 4 5 6 7 6 7

32. Electron Configuration Exceptions Chromium  Expect: [Ar] 4s2 3d4 Actually: [Ar] 4s1 3d5 Sometimes, in order to atleast get a half full d sublevel, some 
elements will cheat a bit and steal electrons from an s sublevel. To 
see why this can happen we need to examine how "close" d and s 
sublevels are. 1 2 3 4 5 6 7 Cr 6 7

33. Energies of Orbitals Because of how close the f 
and d orbitals are to the s 
orbitals en electron can easily 
be taken from the s orbital 
(leaving it half full) and given 
to the f or d orbital, causing 
them to also be half full. Its kind of like borrowing a cup 
of sugar from a neighbor. 
You'd only borrow it from 
someone you were close to, 
and only if you needed it. It's 
the same thing for electrons. 7f 7d 6f 7 7p 6d 5f 6 7s 6p 5d 4f 5 6s 5p Energy 4d 4 5s 4p 3d 3 4s 3p 2 3s 2p 1 2s 1s

34. Electron Configuration Exceptions Copper  Expect: [Ar] 4s2 3d9 Actually: [Ar] 4s1 3d10 Copper gains stability with a full d-sublevel by taking 
electrons from the s orbital. Cu 1 2 3 4 5 6 7 6 7

35. The Periodic Table Now that we know where (or approximately 
where) to find the parts of atoms, we can 
start to understand how these factors all 
come together to affect how we view the 
elements. We can look at them as individual yet 
interacting chemicals, and we are able to 
group them based, not only on the 
properties they present when in isolation, 
but also the properties they reveal when 
exposed to other elements or compounds.

36. History of the Periodic Table Dmitri Mendeleev, building on the ideas from chemists before him, developed the 
modern periodic table. He argued that element properties are 
periodic functions of their atomic weights. 
We now know that element properties are 
periodic functions of their atomic number. 
By elemental properties, we are describing 
both physical and chemical properties. Atoms are listed on the periodic table in rows, based on 
number of protons.

37. Information on the Periodic Table A periodic table usually has the following information: Name of Atom Element Symbol - the one or two letters 
designating the atom Atomic Number - the number of protons in that particular atom Atomic Mass - the average atomic mass for that atom NOTE: A periodic table may have more information or less information, depending on the publisher and intended use.

38. Periodic Table The periodic table is made of rows and columns: Rows in the periodic table are called Periods. Columns in the periodic table are called Groups. Groups are sometimes referred to as Families, but "groups" is more traditional.

39. groups 1 2 3 periods 4 5 * 6 7 ** * 6 ** 7