Periodic Table 1
Elements in the Periodic Table are in order of their:
Atomic number
How many sig figs in 2.004
4
This element does not belong to the same family as the other elements in its group
Hydrogen
The energy required to remove an electron from an atom
Ionization energy
How do you find the number of neutrons?
Mass number minus atomic number
The three classes of elements are:
Metals, nonmetals and metalloids
answer in the correct sig figs: 1200 x 3.506
4200
The very reactive elements in group 1 are known as this.
What are alkali metals?
This is the trend on the periodic table with regard to atomic radius size.
Increases top to bottom within a group and decreases from left to right across a period?
What do periods tell us about the atomic structure?
Number of electron shells or energy levels
This class of elements are good conductors of heat and electric current.
Metals
The reactive elements in group 2 are known as this.
What are alkali earth metals?
Metals form this type of ion.
Cations or positively charged atoms
What do groups tell us about the atomic structure?
Number of valence electrons
This class of elements are poor conductors of heat and electricity.
Nonmetals
The elements in group 17 are known as this.
What are the halogens?
Nonmetals form this type of ion.
Anions or negatively charged atoms
Why does neon have a higher ionization energy compared to fluorine?
More protons, so more attractive force holding onto its electrons.
This class of elements have properties of both metals and nonmetals.
Metalloids
The nonreactive elements in group 18 are known as this.
What are the noble gases?
Which element has the smallest radius?
Helium
Why does potassium have a lower ionisation energy than sodium?
Potassium's valence electrons are further from the nucleus, therefore have less attractive force compared to sodium.