What do groups affect
The number of electrons in the outer energy level in an element
What do periods affect
The number of energy levels in an element
Why are group 0 elements less reactive
They are inert because they have a full, stable outer shell so they have no energetic need to gain or lose electrons
Who made the first periodic table and when
In 1808, John Dalton arranged the atoms in order of atomic weight
Who made the second periodic table, how and when
In 1865, John Newlands ordered it by atomic weight but with more elements. He realised that every 8th element had similar properties. This was called the Law of Octaves.
Who made the final periodic table, how and when
In 1869, Dmitri Mendeleev made his own table according to the atomic weight and similar properties. He left gaps because he believed unknown elements would fill in those gaps, and he was right.
What was the issue with Mendeleev ‘s table and how is it solved now
Some elements were positioned based off properties solely and not atomic weight. When protons were discovered, scientists ordered the elements on atomic number.
Example of a problem with Mendeleev’s table
Argon was heavier than potassium but was still placed before potassium so it could fit with the other noble gases
Why are transition metals similar in terms of electronic structure
Thet have similar electronic structures, with the same number of outer-shell electrons and a partially filled d-subshell that behaves similarly during reactions.
Why are there no transition metals between Mg and Al
Transition metals are the elements that fill a d subshell, and electrons only start entering the d subshell from Period 4 onwards.
What are properties
A characteristic or attribute by which we can describe something
Issue with Newland’s table
There were 2 elements in one space sometimes, there was no space for new elements and it only worked for the first 16 elements, not all
What are the two types of properties
Physical and chemical
What are physical properties
Observations made when substances haven’t gone under a chemical change
What are chemical properties
Properties of a substance that describe how it reacts with other substances and changes into something new
Physical properties of metals
- Lustrous (shiny)
-Malleable (easy shaping)
-Ductile (can draw into wire)
-High density
-High m.p
-High conductivity
-Sonorous (ringing sound when banged)
Physical properties if non metals
-Dull
-Brittle (breaks easily)
-Low density
-Low m.p
-Insulators
What happens when metals react with oxygen
Metal oxides
What happens when metals react with acids
A metal salt and hydrogen is formed
Are metal oxides acidic or basic
basic
Are non-metal oxides acidic or basic
Acidic
What charge do compunds always have
Neutral
How does calculating an ion charge work
If an element lost 2 electrons to get a full outer shell, this means there are 2 more protons than electrons so the charge is +2
What are ions
An atom or group of atoms with a charge (positive or negative) due to gain or loss of electrons
