Structure of an Atom
This subatomic particle determines the identity of an atom.
protons
What is the mass number of Carbon-14?
14
When an element has a charge of zero the number of protons and electrons are ___________.
equal
Which family on the periodic table has the following properties?
- the most reactive non metals
- exist as solid, liquid, and gas at STP
Halogens (7A)
Which of the following elements has the lowest ionization energy?
As, Se, Br, Kr
Arsenic (As)
Ernest Rutherford used this experiment to determine that there is positively charged, dense nucleus at the center of the atom.
Gold Foil Experiment
An unknown element has 12 protons, 13 neutrons, and 14 electrons. What is the mass number of this element?
25 amu
What is the charge of an unknown element that has 6 protons, 6 neutrons, and 7 electrons?
-1
Give three (3) properties of metals.
They are good conductors of heat and electricity, malleable, ductile, most are solid at room temperature, lustrous (shiny), lose electrons, form cations
Which of the following elements is the most electronegative?
Na, K, Rb, Cs
Sodium (Na)
When an element changes it's number of neutrons it becomes this.
An Isotope
An unknown element has 12 protons, 13 neutrons, and 14 electrons. What is the charge of this element?
-2
When a metal loses electrons to become a cation, this ion is larger or smaller than the neutral parent atom?
Smaller
This family contains elements that are not reactive and all elements in this family exist as a gas.
Noble Gases
Which of the following elements has the smallest atomic radius?
Be, Mg, Ca, Sr
Beryllium (Be)
J.J. Thomson used this experiment to confirm that electrons existed in atoms.
Cathode Ray Experiment
Chromium-53 has how many protons and neutrons?
Protons = 24
Neutrons = 29
Neils Bohr determined that electrons exist is these.
Orbitals / Electron Cloud
Which family on the periodic table has the following properties?
- most reactive metals
- extremely reactive with water
Alkali Metals
What is electronegativity?
An elements ability to attract electrons to itself
Which of Dalton's postulates were incorrect?
All matter consists of indivisible particles called atoms & All atoms are identical (subatomic particles exist as well as ions and isotopes!)
Lithium-6 and Lithium-7 are the two naturally occurring isotopes of lithium. They have a percent abundance of 7.5% and 92.5% respectively. Determine the average atomic mass based on this information. Your answer should correct to the 1/1000th for these points.
6.925 amu
Nitrogen tends to form an anion with a charge of -3. How many protons, neutrons, and electrons are in an anion of Nitrogen-14?
protons = 7
neutrons = 7
electrons = 10
Name the seven (7) metalloids on the periodic table.
Boron (B), Silicon (Si), Germanium (Ge), Arsenic (As), Antimony (Sb), Tellurium (Te), Polonium (Po)
This periodic trend describing the amount of energy needed to remove an electron from the valence shell is ________________.
ionization energy