C2, The Periodic Table Flashcards
How were elements are arranged in 1800s and why
Via atomic mass because that’s all they could measure
What was Mendeleev’s breakthrough
In 1869 Mendeleev took 50 elements and arranged them into a table of elements with various gaps
Why were gaps left and what they indicate in Mendeleev’s periodic table
The gaps were left to make sure the elements with similar properties stayed in the same group
The gaps indicated the existence of unknown elements and allowed Mendeleev to predict their properties
What does the atomic number determine
An elements position in the periodic table
What determines chemical properties
The number of electrons in the outer most shell of an atom
What is the group number equal to
The number of electrons in the outer most shell of all elements in that group
Why are noble gases unreactive
Because they have stable electron arrangements because they have a full outer most shell
What happens to melting points in the alkali metals (group1)
They decrease going down the group. The boiling points do the same
What can all the alkali metals react with
They can react with water to produce hydrogen and alkaline solution containing the metal hydroxide
How does the reactivity change in alkali metals
They increase when going down the group that’s why francium is so much more reactive than lithium
How do melting and boiling points change in group 7 the halogens
Melting and boiling points increase going down the group however they already have relatively low melting and boiling points in comparison
What type of ion does halogens form
They form irons with a -1 charge in the ionic compounds with metals
They also form covalent compounds by sharing electrons with other non-metals
How does the reactivity of halogens change
They decrease whilst going down the group
What is electrostatic attraction
The attraction between electrons in the outer most shell and the nucleus
What does electrostatic attraction depend on
1) The distance between the valence shell and nucleus
2) The number of occupied in shells on an electron which provide a shielding affect
3) The size of the positive charge on the nucleus
How did the size of atoms change regarding the amount of electrons
Larger atoms lose electrons more easily going down the group whereas they gain electrons less easily going down the group
Features of transition elements
They have much higher melting points and density and they are also stronger and harder but are much less reactive
What ions can transition metals form
They conform are you into different charges and they are very important industrial catalysts
