Atoms and Subatomic Particles
What are the three main subatomic particles?
Protons, neutrons and electrons
For an atom to become an ion, it can ______ or lose electrons.
gain
What does the atomic number represent?
number of protons
What type of reaction joins two elements together to form one compound?
Synthesis
3.25 x 1025 atoms of neon gas equals how many moles of neon gas?
54.0 mol Ne
Where are protons and neutrons found?
Nucleus of the atom
An atom has an electron configuration of 1s22s22p4. This would be an atom of..
oxygen
Which group contains very reactive metals?
Group 1 (alkali metals)
In a decomposition reaction, what happens?
One reactant breaks down into simpler substances
What mass of Mg would be needed to make 15g of MgCl2 , when reacted with an excess of HCl?
3.8 g
What is the mass number?
number of protons + neutrons
What would be the orbital electron configuration for an atom of Aluminium?
1s22s22p63s23p1
Which side of the periodic table contains non-metals?
Right side
What type of reaction occurs when one element replaces another element in a compound?
Single replacement
What is the empirical formula of a compound that contains 0.783 g of Carbon, 0.196 g of Hydrogen and 0.521 g of Oxygen?
C2H6O
An element has an atomic number of 15 and a mass number of 31.
How many neutrons does it have?
16
What would an atom in Group 17 do to form an ion?
Gain one electron
Why are elements in the same group chemically similar?
Same number of valence electrons
What type of reaction is this?
Na₂S + 2HCl → 2NaCl + H₂S
Explain why it fits that category.
Double replacement
Two compounds exchange elements
Na₂S and HCl swap partners → NaCl and H₂S
Sample(3.585 g) contains 1.388 g of C, 0.345 g of H, 1.859 g O and its molar mass is 62 g. What is the molecular formula of the sample?
C2H6O2
An atom of element X has 20 protons, 18 electrons and 22 neutrons.
Identify the element, and state its charge
Calcium 2+
What is the electron configuration of an isotope of nitrogen-15?
1s22s22p3
Explain why elements get more reactive as you go down Group 1.
Outer electron is further from the nucleus → weaker attraction → easier to lose
Balance the combustion of ethanol:
C₂H₅OH + O₂ → CO₂ + H₂O
C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O
Solid calcium carbonate, CaCO3, is able to remove sulphur dioxide from waste gases by the reaction (balanced as written):
CaCO3 + SO2 + other reactants -> CaSO3 + other products.
In a particular experiment, 255 g of CaCO3 was exposed to 135 g of SO2 in the presence of an excess amount of the other chemicals required for the reaction.
a) What is the theoretical yield of CaSO3?
b) If only 198 g of CaSO3 was isolated from the products, what was the percentage yield of CaSO3 in this experiment?
a) 253 g CaSO3
b) 78.3 %