Homework # 2 week one semester two

1. Another term for:
1. Row- period
2. Column- group or family
2. The names and symbols of two elements in the alkali metal family are sodium (Na) and potassium (K).
3. Consider the noble gas family:
1. The noble gases are located on the far right of the periodic table and they are the last of the columns of elements.
2. Noble gases are all gases at room temperature.
3. Noble gases are non reactive with other substances and rarely form compounds.
4. Predicted formulas
1. Mg and F= MgF₂
2. Ga and P= GaP4
5. Estimated melting point of potassium= 98+39= 137/ 2= 68.5 ^oC
6. The boiling point of Cl would be lower than the boiling point of I because Iodine is lower in the period than Cl.
7. Following table answers 19
8. 10. The student’s mistake is common because she or he mistook 2⁺ to mean that the element had to gain two electrons; however, in order for an element to have a 2⁺ charge the element has to lose 2 electrons not gain them.
   11. The mass number for each element in the table created in number 19 are: C= 12, C=13, Ca= 41, Pt= 195, U=238.
   b. The element that has two isotopes in the table is Carbon with an isotope of regular carbon with a mass of 12 and an isotope of a Carbon with 7 neutrons with a mass of 13.
   12. The mass number of 266 is not a sufficient characteristic of a new element because there is no way to tell how many protons, electrons, and neutrons there are in the element just by the atomic mass; the element could be unbalanced, which would classify it as an ion, not an element. 
   
   
   
   
   Following tables answer 19 and 20