Supplemental Instruction
Iowa State University / Leader: / Tina Akinyi
Course: / Chem 177
Instructor: / David Appy
Date: / 1/25/15
This worksheet contains material covered during the 1/23/15 (Friday) lecture.
- Writing symbols for atoms:
Tin has several isotopes, three of which have mass numbers 112, 115 and 117.
a)Write the complete chemical symbol of each isotope (subscripts and superscripts)
b)How many neutrons are in an atom of each isotope?
- Atomic weight= m1f1+m2f2+m3f3+…. Where mn represents the isotope mass and fn represents the fractional abundance of the isotope.
a)Copper has two naturally occuring isotopes. Cu-63 has an atomic mass of 62.9296 amu and an abundance of 69.15%. What is the atomic mass of the second isotope? What is its nuclear symbol?
b)Nitrogen is made up of two isotopes, N-14 and N-15. Given nitrogen's atomic weight of 14.007, what is the percent abundance of each isotope?
(Dr. Appy suggested a similar question in class and he gave a very useful hint as to how it could be solved)
The periodic table
Periodic table- The arrangement of elements in order of increasing atomic number, with elements having similar properties placed in vertical columns.
- In your own terms define a Period and aGroup.
- Match the following statements with the respective pioneers
A- John NewlandB-Dmitri Mendeleev
a)Noticed that by arranging the elements in order of increasing atomic mass every eight element seemed to have similar properties
b)In 1869 he arranged the 50 or so known elements in order of atomic mass, putting elements with similar properties in the same vertical group, and leaving gaps for unknown elements, yet to be discovered.
c)Is credited as being the Father of the modern periodic table
d)His idea became known as ‘the law of Octaves’. It did not work for the fourth period with the transition metals.
- Give five characteristics of metals and non-metals and define each characteristic
- When atoms meet or bond, two possibilities can result. Either a molecule/ molecular compound can form, or an ionic compound can form. What are some characteristics of molecules and ionic compounds? Here are some ideas
Involves the sharing of electrons, involves the aggregation of ions, the ions are held together by electrostatic attraction, involve the taking/losing of electrons, typically involve a nonmetal reacting with another nonmetal, form lattices etc.
7. Remember that atoms gain/lose electrons in order to resemble the nearest noble gas