Chemistry Quiz 3 (Unit 4) Review Questions
a. Lead(IV) sulfide
PbS2
When do you have to use Roman numerals when naming compounds? Why do you have to use Roman numerals in these cases but not others?
Roman numerals are used in naming ionic compounds when the metal cation forms more than one ion. The metals that form more than one ion are the transition metals, although not all of them do this.
f. Tin(II) oxide
SnO
b. Strontium bromide
SrBr2
For main group elements, what do you know about the element's electrons based on its position on the periodic table? For example, what can you say about the electrons in the element strontium? In the element radon?
The Period tells you how many shells the electrons has and the Group tells you how many valence electrons (outermost electrons) there are. For example, strontium has 2 valence electrons and 5 Shells. Radon has 8 Valence Electrons and 6 shells.
Why can you use a main group element's position on the periodic table to predict the charge it forms an ion? Discuss the relationships between an element's position, valence electrons, and type of ion formed.
The difference in valence electrons tells the charge of the element. If the element must gain electrons (move to the right) it is an anion, if it loses elements (moves to left) its a cation.
What part of a compound is responsible for a color emitted during a flame test and what is the evidence that it's this specific part of the compound and not the other part, or the compound as a whole?
The metal ions are responsible for the color emitted during a flame test.
c. AlF3
Aluminum Fluoride
d. BaO
Barium Oxidei
d. CrI3
Chromium(III) iodide
c. Co3P2
Cobalt(II) Phosphide
a. Cesium nitride
Cs3N
b. Copper(II) nitride
Cu3N2
Explain why elements on the left side of the periodic table lose electrons instead of gaining them.
Elements on the left side of the periodic table lose electrons instead of gaining electrons because it is easier to lose valence electrons to get to a total number of 0 then gaining electrons to get to a total number of 8.
Which elements are most similar to a given element on the periodic table? Why is this?
Elements that are most similar to each other are elements in the same column. This is because they have the same number of valence electrons meaning they react the same way.
e. Iron(II) phosphite
Fe3(PO3)2
Write the name and formula for the compound that forms between magnesium and oxygen. Explain why this specific combination is correct and how every other combination is incorrect both in terms of charge and in terms of valence electrons.
Magnesium Oxide-MgO; Because magnesium has a positive 2 charge and oxygen has a negative 2 charge they cancel out and from a neutral compound. In terms of valance electrons, magnesium transfers two electrons to the oxygen molecule so that both elements can obtain a number of valance electrons that will make them both stable.
g. Mn(CO3)2
Manganese(IV) Carbonate
h. NiN
Nickle (III) nitride
Explain why the noble gases are the most chemically stable elements. How can the atoms of other elements achieve this stability shown by the noble gases?
Noble gases are the most chemically stable elements because their outermost shell holds the maximum number of valence electrons it can hold. Other atoms of other elements achieve this stability by trading electrons and become ions.
Discuss the two possible cases where an atom is not neutral and what causes this (One way to think about this is to think about when atoms are neutral, and then think about when think about when this is not followed).
Two possible cases where an atom is not neutral if it doesn't have a multiple of 8 valance electrons (including 0) so the element loses or gains electrons and becomes an ion or when the number of protons and neutrons are unbalanced.
Why is color given off during a flame test?
When heated, the electrons gain energy, and are 'excited' into higher energy levels; however, the electrons occupying these levels are more energetically unstable, and they tend to fall back down to their original energy levels, releasing energy as they do so. This energy is released as light, with the characteristic flame colors of different metal ions due to varying electron transitions.
In as much detail as you can, describe what occurs when an atom of sodium and an atom of chlorine come close together. Describe this process both in words and using correct models.
When sodium and chlorine atoms come together to form sodium chloride (NaCl), they exchange an electron. The sodium (Na) transfers one electron to the chlorine (Cl) atom so that they both have a number of valance electrons that make them stable. Because the sodium gave one electron away it becomes positively net charged, likewise because the chlorine received one electron it becomes negatively net charged. The two atoms are then attracted to each other and form an ionic compound. (look at study guide for image)
Draw a simple atomic model for an element with two shells and two valence electrons. Using arrows, illustrate what you are describing in the previous question to explain why color is given off during a flame test.
look at study guide lol
