Periodic Table Flashcards
(32 cards)
Atomic Number
Number of protons
Mass Number
Protons and neutrons
What are the rows of the periodic table called?
Periods
What are the columns of the periodic table called?
Groups
Elements in the same group have the same…
number of electrons in their outer shell
What does the group number tell you about the element?
How many electrons are in the outer shell and have similar properties
How were elements first organised?
By their mass
How do we order elements now?
Atomic number (protons)
Who first devised a periodic table?
John Newland
What was wrong with Newlands first periodic table?
Some elements were put in the wrong place
Who realised there might be undiscovered elements?
Dmitri Mendeleev
How did Mendeleev change the periodic table?
He added gaps to Newlands table for undiscovered elements that he predicted the mass and properties of
How is the modern periodic table different from Mendeleevs?
The gaps are filled in and the discovery of protons and isotopes
What happens when metals react?
They lose 1 or more electrons to form positive ions
Properties of metals
High melting and boiling points, good conductors, all solid except mercury at room temp
What happens when non metal react?
Gain electron to form negative ions or share electrons to make neutral molecules
Properties of non metals
Lower melting and boiling points, found in gases, don’t conduct
What are group one metals also known as?
Alkali metals
Features of alkalis
Soft and low ish melting points
How is reactivity affected going down group 1?
More reactive
How does lithium sodium and potassium react with water?
Floats and releases hydrogen bubbles, floats and melts moving quickly across the water, floats with more rigorous reaction
Why does reactivity increase down group 1?
Because they have more shells, therefore the attraction between the outer electron and the nucleus is weaker and so the electron is easier to lose
What are group 7 elements called?
Halogens
Does reactivity increase or decrease down the group?
decreases due to more shells therefore weaker attraction for gaining an electron
