Chem A Flashcards
(18 cards)
element
A substance made up of only one type of atom
compound
A substance made up of two or more
different elements bonded together
How is an atom structured
electrons orbiting and protons and neutrons in the nucleus
how are electrons structured
2 electrons in first shell and 8 in all the other shells
isotopes
same element with a different number of neutrons
rutherford gold foil experiment
fired alpha particle at gold foil
most alpha particles went straight through but some deflected.
proved atomic structure was mostly empty space with a small positively charged nucleus
how did mendeleev arrange periodic table
arranged by atomic mass and left gaps for undiscovered elements
how modern periodic table is arranged
elements arranged by atomic number. Elements in the same group have similar properties
trends in the periodic table
group number shows number of outer electrons. Each group has an increase of 1 electron in there outer shell.
properties in group 1 metals
soft,low melting point, low density, metals, conduct electricity
when group 1 elements react with water.
PH of solution increases, fizzing/bubbling, metal floats on water as its less dense than water, metal becomes a molten sphere. Pottasium produces a lilac flame.
trends in group 1 metals
elements in group 1 become more reactive as you go down the group as there is a larger gap between the nucleus and the outer shell therefore weaker electrostatic forces of attraction so electrons are more easily lost
appearance of group 7 metals
fluorine: colorless gas
chlorine:pale yellow
bromine:orange
iodine:grey solid with a purple vapour
trends in group 7 physical properties
gets darker and boiling point increases
trends in group 7 reactivity
Halogens are less reactive as you go down the group due to outer electrons being further away from the nucleus meaning weaker electrostatic forces of attraction making it weaker electron is less easily gained
displacement reaction
a more reactive element displaces a less reactive element for eg
chlorine+sodium bromide=sodium chloride+bromine
properties of group 0 elements
they are noble gases and unreactive as they have a full outer shell
properties of transition metals
hard,conduct electricity and heat, high melting point, malleable
