4: periodic table + atoms
molecular compounds _______ electrons while ionic compounds ______ electrons
options: transfer or share
share, transfer
(bonus: what two kinds of atoms are molecular/ covalent bonds formed between?)
In a polar covalent bond are electrons equally or unequally shared?
What is the number of electrons lost or gained when the element, Sr, forms its ions?
2 electrons lost
(what is the symbol of the ion?)
Draw the lewis structure for OF2
draw on board
Does electronegativity decrease or increase as you go from Mg to Ba?
decrease
How many moles of S are present in 3.0 moles of Al2(SO4)3? How many grams of S?
What is the symbol of the element with the least metallic character in group 4?
C
Write the formula and name for compound formed with the silicon and oxygen
SiO2
(ionic or molecular?)
Draw the Lewis structure and predict the molecular shape of SI2
Draw on board
bent (109 °)
(name it!)
For the bond C—O, indicate the partially positive end with δ+ and partially negative end with δ–.
Then, draw the arrow to show the dipole.
(hint: use the electronegativity values)
draw on board
C is δ+ and O is δ–
How many moles are there in 100g of O2 (hint: calculate molar mass)? How many molecules of O2 are present?
3.125 moles, 1.88*10^24
fill in the blanks:
atom/ion formula: _______
no. of protons: 8
no. of electrons:_______
no. of electrons gained: 2
O2-, 10
which of the following pairs of elements would likely form an ionic compound
(a) lithium and chlorine
(b) oxygen and bromine
(c) potassium and oxygen
(d) sodium and neon
(e) cesium and magnesium
(f) nitrogen and iodine
a and c
name it!
(ionic is between a cation and anion only - charged molecules (ions). So it would generally be between metals (NOT metalloids) and nonmetals.
Name and draw the electron dot formula of BCl3
Boron trichloride (draw on board)
What rule does this not follow?
Is the molecule CF4 polar or non-polar?
(hint: draw the structure)
non-polar, draw on board
(Name it!)
Balance this equation
Fe2O3 (s) + C (s) --> Fe (s) + CO (g)
What type of reaction is this?
Fe2O3 (s) + 3C (s) --> 2Fe (s) + 3CO (g)
Single replacement
What is the group number of representative element X in the ionic compound: Al2X3
(hint: identify the charge on cation)
Group 6
Name the ionic compound Mn2O3
manganese (III) oxide
Predict the molecular shape and polarity of PF3
trigonal pyramidal, polar
dipole-dipole attractions
How does adding a catalyst change the rate of reaction? (decrease/increase)
increase
Silicon has 3 naturally occurring isotopes with their mass and abundances given-
Si-28 (27.977 amu): 92.23%
Si-29 (28.9976 amu): 4.68%
Si-30 (29.974 amu): 3.09%
Calculate the atomic mass of Silicon using the weighted average mass method.
28.09 amu
(extra: how do you tell which is the most prevalent isotope without the abundance)
chromium (II) nitrate
What is the molecular shape of SiCl4?
(hint- draw out the lewis structure)
tetrahedral
(is it a polar or non-polar compound?_
What is the major type of attractive forces between particles in the following compounds?
options: dispersion forces, dipole-dipole attractions or hydrogen bonds
1) NF3
2) H2O
3) CF4
1) dipole-dipole
2) Hydrogen bond
3) dispersion forces
(which of those 3 intermolecular forces are the strongest? Weakest?)
A 10.0 L balloon contains helium gas at pressure 655 mmHg. What is the final pressure (in mmHg) if the volume of the balloon is now 1250 ml?
(Assume temperate and amount of gas is same)
Hint: Boyle's Law
5240 mmHg