The Periodic Law (Unit #5) Study Guide
1. Who is credited with developing the first successful periodic table? __Mendeleev_________
2. This person used atomic _mass_____ and _properties___ of elements to arrange the elements
in periodic order.
3. Henry Moseley found that elements in the periodic table fit into patterns better when
arranged in increasing order according to nuclear charge or _atomic number______.
4. The _periodic_______ law states that the physical and chemical properties of the elements
are periodic functions of their _atomic___________ numbers.
5. The modern periodic table is the arrangement of elements in order of their _atomic_______
_number_____ so that elements with similar properties fall into the same column, or group.
6. In the periodic table elements are ordered according to their _increasing_____ (increasing or
decreasing) atomic number.
7. Who discovered the noble gas, argon? __Sir William Ramsay____________________
8. The _electron_________________ __configuration_________ of an atom’s highest occupied
energy level generally governs the atom’s chemical properties.
9. The elements are arranged vertically in the periodic table in __groups_______________.
10. The elements are arranged horizontally in the periodic table in __periods________________.
11. How is the length of each period in the periodic table determined? _number of sublevels
being filled_____
12. What are the four “blocks” of the periodic table? __s, p, d, f____________
13. How many elements are in a period in which only the s and p sublevels are filled? ___8____
s, p, d? __18_______ s, p, d, f ___32______
14. The _period____________ of an element can be determined from its electron configuration.
15. Calcium (Ca) has the electron configuration [Ar]4s2. Based on the information in question
12 what period would calcium be in? ____4________
16. Group 1 elements are known as _alkali_____________ __metals______________.
17. Group 2 elements are known as __alkaline________ __earth________ ___metals_________.
18. What elements are special cases in the classification of elements? _hydrogen_____________
and ___helium_______________
19. The d-block elements are also known as ___transition___________________ metals.
20. Which group of metals are the most reactive? _Group 1___________________
21. Which group is the most reactive of the nonmetals? _Group 17________ These elements are
commonly known as ___halogens______________.
22. _Atomic______ _radius__________ is one-half the distance between the nuclei of identical
atoms that are bonded together.
23. Across a period in the periodic table, atomic radii __decreases______. Down a group on the
periodic table atomic radii __increases______________.
24. The energy required to remove one electron from a neutral atom of an element is the
_ionization____________ _energy________________.
25. Ionization energy _increases____________ across a period and _decreases___ down a group.
26. The energy change that occurs when an electron is acquired by a neutral atom is called the
atom’s _electron___________ ___affinity_____________.
27. Across a period it is __easier_______ (easier or harder) to gain electrons. Down a group it is
_harder___________ (easier or harder) to gain electrons.
28. A positive ion is known as a __cation____________ and a negative ion is known as a
___anion______________.
29. Compare the radius of a positive ion to the radius of its neutral atom. ___ion is smaller than
neutral atom______________________________________________________________
30. Compare the radius of a negative ion to the radius of its neutral atom. _ion is larger than
neutral atom______________________________________________________________
31. Ionic radii _decreases___________ across a period and _increases_________ down a group.
32. The electrons available to be lost, gained, or shared in the formation of chemical compounds
are known as _valence___________ __electrons_______________.
33. _Electronegativity_________________ is a measure of the ability of an atom in a chemical
compound to attract electrons. Which is the most electronegative element? _fluorine_____
34. Electronegativity _increases_________ across a period and _decreases______ down a group.
35. Which is the most electronegative element? _fluorine___
36. Consider an element whose outermost electron configuration is 4s23d104px.
a. To which period does the element belong? __4_______________
b. If it is a halogen, what is the value of x? ___5________________
37. In which block are the metalloids found, s, p, d, or f? _____p_______________
38. In which block are the hardest, densest metals found, s, p, or d? ____d________
39. Which has the largest radius, Al or In? ____In_________________
40. Which has the largest radius, Ca or Se? ____Ca________________
41. Which has the largest radius, Ca or Ca2+? ___Ca________________
42. Match the following:
__c___ main group elements
__d___ lanthanides and actinides
__e___ transition metals
__a___ alkali metals
__b___ halogens
a.
b.
c.
d.
e.
Group 1 elements
Group 17 elements
elements of the s and p blocks
elements that make up the f block
entire set of d block elements