Chemistry
Worksheet : Chs. 7-9 ; Obj. 1-11
Name :
Date :
A. Read pp. 187 - 216 and answer the following questions :
1. ___________________________________ are the electrons in the highest occupied energy level of an element's atoms.
2. Circle the valence electrons in the following electron configuration of magnesium.
2
2
6
2
1s 2s 2p 3s
3. _____ (T/F) The number of valence electrons is very important in determining the chemical properties of an element.
4. _____ (T/F) The elements of a group have different numbers of valence electrons.
5. _____ (T/F) The representative groups 1A-7A have the same number of valence electrons as their group number.
6. State the number of valence electrons of the following elements :
_____ oxygen
_____ argon
_____ fluorine
_____ helium
_____ lithium
_____ krypton
_____ magnesium
_____ neon
_____ potassium
7. _____ (T/F) Valence electrons are usually the only electrons involved in a chemical bond.
8. _____ (T/F) Electron dot structures show the valence electrons as dots around the symbol of the element.
9. Show the electron dot structures of the following elements :
Calcium
Ca
chlorine
Rubidium(Rb - 37)
Rb
Cl
tin (Sn - 50)
Sn
10. _____ (T/F) The higher the energy level, the more stable an atom or ion is.
11. _____ (T/F) Stable electron configurations have a low level of energy.
12. State the octet rule and who proposed the octet rule and when.
2
2
6
13. Neon has the following electron configuration : 1s 2s 2p . Answer the following questions true or false based on this
electron configuration.
_____ Neon has a very stable electron configuration.
_____ Neon has a low level of energy.
2
2
6
_____ Magnesium (1s 2s 2p 3s2) needs to lose two electrons to become as stable as neon.
_____ Magnesium will have a negative two (2-) charge after it loses two electrons.
_____ Fluorine will need to gain one electron to get the electron configuration of neon and will have an ionic charge of 1-.
14. _____ (T/F) Calcium will need to lose two electrons to get the electron configuration of argon.
15. _____ (T/F) All the alkaline earth elements (Group 2A) will need to lose two electrons to obtain a noble gas electron
configuration.
16. _____ (T/F) All the elements of the oxygen group (Group 6A) will need to gain two electrons to obtain the electron
configuration of a noble gas.
17. _____ (T/F) All the elements of Group 6A are likely to have a 2- ionic charge.
18. _____ (T/F) All the elements of group 3A (aluminum group) will probably gain 5 electrons to get a noble gas electron
configuration.
19. __________________________________________ are charged atoms or groups of atoms.
20. __________________________________________ are positively charged ions.
21. __________________________________________ are negatively charged ions.
22. _____ (T/F) Anions are formed by the loss of electrons.
23. _____ (T/F) Cations are formed by the gain of protons.
24. ____________________________ ions are the ions of the halogens and have a 1- charge,
25. _____________________________________ compounds are composed of positive and negative ions.
26. _____ (T/F) A formula unit shows the smallest whole-number ratio of ions in a molecular compound.
27. _____ (T/F) Ionic compounds are composed of nonmetallic elements.
28. _____________________________________ compounds are composed of molecules.
29. _____________________________________ show the kinds and numbers of atoms in the smallest representative unit of a
substance.
30. _____________________________________ are neutral groups of atoms that act as a unit.
31. _____ (T/F) Molecular formulas show the number and kinds of atoms present in an ionic compound.
32. _____ (T/F)Molecular compounds are composed of a metal and a nonmetal.
33. Identify the following substances as ionic(I) or molecular(M).
_____ H2O
_____ C4H8
_____ AlCl3
_____ S2O5
_____ C12H22O11
_____ LiF
B. Read pp. 274-275 and answer the following questions :
34. State the law of definite proportions.
35. State the law of multiple proportions.
36. Determine the ratio of oxygen for the two compounds carbon monoxide and carbon dioxide.