Topic 1 - Atomic Structure and Periodic Table Flashcards
What’s an atom?
All substances are made of atoms. An atom is the smallest part of an element that can exist.
How many different elements are there?
100
What are formed when elements react?
Compounds
What happens in a chemical reaction?
New substances are formed
What’s a compound?
Two or more elements chemically combined
Compounds can only be seperated into their elements by..?
Chemical reactions
What’s a mixture?
Two or more elements or compounds not chemically combined
Dalton’s atomic model?
Atoms are tiny sheres that can’t be divided
Plum pudding model?
Ball of positive chareg with negative electrons embedded
Nuclear model?
Small, dense, positive nucleus. Electrons outside the nucleus. Most of the atom is empty space
How did Nils Bohr adapt the nuclear model?
Electrons orbit the nucleus at specific distances
Order of subatomic particle discovery?
Electron, proton, neutron
Who discovered the neutron?
James Chadwick
Charge on a proton?
1
Charge on a neutron?
0
Charge on an electron?
-1
Why do atoms have no overall charge?
Number of protons = number of neutrons
Atomic number
Number of protons
Atoms of the same element have the same number of..?
Protons
Atomic radius
0.1nm (1x10-10m)
Nuclear radius
1x10-14m
Relative mass of a proton?
1
Relative mass of a neutron?
1
Relative mass of an electron?
Very small
Mass number
Protons + neutrons
Isotopes
Atoms with same number of protons, different number of neutrons
Relative Atomic Mass
Average mass of all the atoms of an element (takes into account abundance)
In which order do electron shells fill?
From nearest the nucleus outwards
Which electron shells have lowest energy?
Nearest the nucleus
In the modern periodic table, elements are arranged in order of..?
Atomic number
What are the columns on the periodic table called?
Groups
What are the rows on the periodic table called?
Periods
Elements in the same group have…
Similar properties
Atoms of the elements in the same group have…
Same number of electrons in their outer shell
How did Mendeleev mostly order the elements in his periodic table?
By atomic weight
What two things did Mendeleev do in the design of his table?
Leave gaps for undiscovered elements, changed the order of some elements
Why was Mendellev’s table accepted?
He predicted properties of undiscovered elements. When they were discovered their properties matched his predictions
What charge ions do metals form?
Positive
Most of the elements in the periodic table are…
Metals
Where are non-metals in the periodic table?
Top right
What is the name of Group 0?
Noble Gases
Why are Noble Gases unreactive?
They have stable electron arrangements
Trend in Noble Gas boiling points?
Increases with increasing relative atomic mass (i.e. going down the group)
What is the name of Group 1?
Alkali Metals
How many electrons do alkali metals have in their outside shell?
1
Alkali metal + oxygen →
Metal oxide
Alkali metal + water →
Metal hydroxide + hydrogen
Alkali metals react with halogens to form…
Salts
How does reactivity of alkali metal change as you go down the group?
Increases
What is the name of Group 7?
Halogens
How many electrons do halgens have in their outside shells?
7
As elements, halogens exist as…
Diatomic molecules
Halogens react with non-metals to form…
Covalent molecules
Halogens react with hydrogen to form…
Hydrogen halides which dissolve in water to form acids
Trend in halogen melting and boiling points?
Increase with increasing relative formula mass (down the group)
How does reactivity of halogens change as you go down the group?
Decreases
A more reactive halogen can…
Displace a less reactive halogen from its aqueous salt
Compared to alkali metals, transition metals…
Less reactive, higher melting points, stronger and harder
Transition metals can form ions with…
Different charges
Appearance of transition metal compounds
Coloured solids and coloured solutions
Transition metal and their compounds are useful as…
Catalysts
