unit 3 - periodic table Flashcards
(36 cards)
what are the two types of number given to each atom
atomic number
mass/nucleon number
Atomic number
no. of protons in an atom
Mass number
no. of protons + neutrons
how to find number fo electrons in an neutral atom
Number of electrons = number of protons in an atom
how to find No. of neutrons in an neutral atom
Mass no - atomic number
How many electrons can fit in the outermost/valence shell
8
octet rule
atoms are most stable when their valence shells are filled with eight electrons.This gives the atom the sameelectronic configuration as a noble gas
Atom which recives an electron becomes a
anion
atom which donates an electrons becomes a
cation
groups in periodic table and trends
veritical coloumns lebeled from 1 - 18.
Elements in the same group have the same number of valence electrons in outermost shell
these elemtns exhibit similar chemical characteristics
Periods in periodic table and its trends
horizontal rows numbered 1- 7
elements in the same period have the same number of energy shells
No. of period = number of energy shells
transition metals properties
- Found in d block of periodic table
- Shiny and lustrous appearance
- Ductile and malleable
- High BP and MP
- High densities
- Good conductors due to free flowing electrons being present
- Form multiple oxidation states
- Can easily gain or lose electrons, but generally form cations
- Less reactive than group 1 and 2 metals
- Form coloured compounds
- used as catalysts
Why are transition metals used as catalysts?
Because they have varying oxidation states and hence variable valency. And can act as oxidising or reducing agents, making them ideal catalysts
halogens
- poor conductors
- Low solubility in water, high in organic solvents
- low MP and BP
- High reactivity because of tendency to gain electrons
- React with metals to form ionic compounds
- have 7 electrons and hence form anion with 1- charge
-found in group 17
Alkali Metals physical and chemical properties
Most reactive, especiallyw with water
Shiny silvery white appearance
Good conductors
Low MP and BP
Soft metals - can be cut by a knife
found in group 1
Lose one electron to form cations with 1+ charge
Why are Alkali Earth Metals so rective with water
Because they only have one valence electron and oxyegn’s electronegatiity which is present in the water, puls that electron very hard, hence resulting in a quick reaction
Alkali earth metals
Shiny appearance
High reactivity but less than alkali earth metals
Fround in group 2
Brittle, but harder than group 1 metals
Low density
Lose 2 valence electrons to Form cations with 2+ charge
Noble gases
found in group 18
no reactivity
already in octet state (no need to gain or lose elctrons)
colourless and odourless
poor conductors
Low MP and BP
No electronegativity value
properties of metals, ion formation and where are they found on the PT
-solids at room temp
-shiny, lusterous and hard
- high MP and BP
- Desne and solid structure
- High conuductivity
-Tend to lose electronws to form +ve ions
- Found on left side of period table
which 2 metals are liquids at room temp?
mercury and gallium
properties of non metals, ion formation and where found on the PT
-mostly gases
- Low BP and MP
-Low density
-Low conductivity
-Gains electrons to form -ve ions
- Found on right side of periodic table
- Soft and Brittle
properties of metaloids, ion formation and where found in PT
-Mostly solids at room temp
- Mid MP and BP
-Intermediate density
- Mid conductivity (more than non metals)
- Can gain or lose electrons depending on element
- Found in between metals and non metals in the periodic table
-soft and brittle
- nonreflective
Periodict trends of Noble gases
Density and BP of noble gases increase as you go down the group
Periodic trends of Halogens (as uu go down the group)
As you go down the group:
Colour gets darker
Reactivity decreases
MP and BP increases
Density increases
