Chapter 1 Est: Atoms, Molecules, And Ions Flashcards
What is periodicity of properties
The repetition of patterns in properties from one period to another.
Describe the shells in atomic radius
The shells are filled with negative electrons which are attracted by the positive protons in the nucleus.
What happens as the atomic number increases?
The number of protons and the proton’s attractive force increases, shrinking the radius of the noble gas
What happens after a noble gas?
The additional electron of next alkali metal will go into a new shell, explaining for the sudden increase in the atomic radius.
What is Electronegativity?
chemical property of an atom that attracts electrons towards itself (from francium to fluorine)
What is Chemical Reactivity
An ability for an atom to lose/gain electrons. An atom is more reactive if it loses or gains electrons easily.
What is chemical reactivity related to?
The number of valence electrons and the distance of the valence shells from the nucleus (Towards Fluorine and Francium)
What happens to the melting point during periods
It increases and then decreases throughout the periods.
What is the base of life and science?
Carbon
What does the atomic number represent?
The number of protons in the nucleus of an atom
What is the relative atomic mass?
It is the mass of an atom measured by comparison with a reference element, carbon-12
What is the unit of measurements for isotopes?
Atomic mass unit (U or AMU)
What is an Isotope?
An atom of an element with the same number of protons but with a different number of neutrons.
What is a mole? describe it.
a counting unit which is similar to a dozen, except instead of 12, its 602 billion trillion. it is the number of atoms in exactly 12g of an element.
give an example of the mole unit.
-1 dozen of cookies= 12 cookies
-1 mole of cookies=6.02 x10 to the power of 23 cookies
