IF you missed them all, you have some serious stinkin' thinking.
watch this:
http://www.youtube.com/watch?v=afnA223Pyz4
for each of the following pairs of elements, give the correct molecular formula, explain how you arrived at this answer( you may use the Bohr model notation, or the orbital model notation, or explain linguistically) and note whether the bonding is covalent or ionic.
( I tried all of them and got the wrong answers so i really need help with these)
Lithium and bromine
radium and fluorine
strontium and oxygen
gallium and chlorine
germanium and oxygen
nitrogen and hydrogen
calcium and hydrogen
sulfur and carbon
2 answers
Here is how you do the simpler ones.
Li and Br. Look at the periodic table. Li is in group I which means it has 1 electron in its outside shell. Br is in group 17 (or VIIA depending upon the system you are using) which means it has 7 electrons in its outside shell. Li wants to lose 1, Br wants to gain 1 so the compound is formed, the electron actually transfers from Li (making it a Li^+ ion) to Br(making it a Br^- ion). The compound is ionic since the electron is transferred and not shared.
Ra is in group II meaning it has two electrons to give away. F is in group 17 meaning it has 7 electrons in the outside shell and needs to gain 1; therefore the Ra atom loses its two electrons to TWO F atoms to make the compound RaF2. It, too, is ionic. When atoms on opposite sides of the periodic table (group I, II, or III metals combine with group 15, 16, 17 non-metals) generally we call those ionic compounds. That's the case with RaF2 an LiBr. When atoms on the same side combine OR combination of elements in the middle with either side, those generally are covalent. Examples are Cl2, H2, CH4, NH3, etc. See if this will get you started.
Li and Br. Look at the periodic table. Li is in group I which means it has 1 electron in its outside shell. Br is in group 17 (or VIIA depending upon the system you are using) which means it has 7 electrons in its outside shell. Li wants to lose 1, Br wants to gain 1 so the compound is formed, the electron actually transfers from Li (making it a Li^+ ion) to Br(making it a Br^- ion). The compound is ionic since the electron is transferred and not shared.
Ra is in group II meaning it has two electrons to give away. F is in group 17 meaning it has 7 electrons in the outside shell and needs to gain 1; therefore the Ra atom loses its two electrons to TWO F atoms to make the compound RaF2. It, too, is ionic. When atoms on opposite sides of the periodic table (group I, II, or III metals combine with group 15, 16, 17 non-metals) generally we call those ionic compounds. That's the case with RaF2 an LiBr. When atoms on the same side combine OR combination of elements in the middle with either side, those generally are covalent. Examples are Cl2, H2, CH4, NH3, etc. See if this will get you started.
4 answers