C3 Periodic table etc Flashcards
Why was this known as a periodic table?
Periodic means repeats regularly, similar properties occur at regular intervals.
Compare the chemical properties of the transition metals with the alkali metals.
Compared with the elements in Gp 1, transition elements are much less reactive and so do not react as vigorously with water or oxygen.
Describe the pattern of the reaction of the alkali metals with water
The further down group 1 an element is the more reactive the element; Sodium floats, fizzes and melts. Potassium floats, fizzes, melts and catches fire (lilac fame)
What difference did this make to the modern periodic table?
The elements were placed in the proper groups.
Write an ionic equation for the reaction of the halogen atom
F + e- → F-
Cl + e- → Cl-
Br + e- → Br-
I + e- → I-
At + e- → At-
Describe the trend in melting point and boiling point going down group 7
In Group 7, the further down the group an element is the higher its melting point and boiling point.
Describe the compounds of the alkali metals with non-metals.
The compounds are white ionic solids that dissolve in water to form colourless solutions
What were Newlands’ octaves?
John Newlands published a table showing that every eighth element had similar properties and could be grouped together.
Compare the physical properties of the transition metals with the alkali metals.
Compared with the elements in Gp 1, transition elements have higher melting points (except for mercury) and higher densities. They are stronger and harder.
How does the electronic structure change across each period in the table?
In period 1 the first shell is filled, in the second period the second shell is filled, etc. e.g. Li- 2.1, Be- 2.2, B- 2.3, C- 2.4.
Explain why scientists thought the periodic table of the elements was a curiosity at first?
The early tables were incomplete, some only worked for the first few elements.
Describe the reaction of the Lithium with water
Lithium floats and fizzes with water, releasing hydrogen gas. It forms lithium hydroxide which dissolves in water to give an alkaline solution that turns UI indicator purple.
How does this change to the order of the elements link to atomic structure?
The periodic table could be used to work out the electronic structure of the elements as well as the number of protons and neutrons.
What is the trend in reactivity in group 7?
In Group 7, the further down the group an element is the less reactive the element
How did Mendeleev overcome problems with the early periodic tables?
When he made his table, Mendeleev left spaces for elements that were yet to be discovered, famously Ga and Ge, so that the other elements fitted into the right groups.
Explain the trend in reactivity in group 7?
The trend in reactivity in gp 7 can be explained because the higher the energy level of the outer electrons the less easily electrons are gained.
OR the gp 7 elements react by gaining/stealing electrons; in smaller atoms the nucleus is more effective at stealing electrons.
How many electrons does iodine have in total and how many electrons are there in the outer shell?
Iodine has atomic number 53 so it has 53 electrons in total. It is in group 7 so iodine has seven electrons in its outer shell.
What is the collective name for the group 7 elements?
They are known as the halogens.
What are the electronic structures of the group 2 metals Be, Mg, Ca?
Be – 2.2 Mg – 2.8.2 Ca – 2.8.8.2 All of the Group 2 metals have two electrons in their outer shells
How do the group 7 elements react with metals?
They react to form ionic compounds in which the halide ion carries a charge of –1.
What is the pattern in melting points and boiling points, going down the alkali metals?
The further down the group an element is the lower its melting point and boiling point.
How were the elements put into columns or groups?
Elements with similar properties are in columns, known as groups.
Write an ionic equation for the reaction of the alkali metal atom
Li → Li+ + e-
Na → Na+ + e-
K → K+ + e-
Rb → Rb+ + e-
Cs → Cs+ + e-
Describe the density of the alkali metals, be specific about the first three?
The alkali metals have low density, the first three (Li, Na, K) all float on water