4.1.2 The periodic table Flashcards
What are ions?
Ions are charged particles. They are formed when atoms lose electrons (positive ions) or gain (negative ions) electrons.
What is formed when a metal reacts with a non-metal?
An ionic compound (made of positive and negative ions).
What is formed when a non-metal reacts with a non-metal?
A molecular compound containing covalently bonded atoms.
Atoms share electrons, as opposed to transferring electrons between each other (cf. ionic compounds).
The columns of the periodic table are called…?
Groups
The rows of the periodic table are called…?
Periods
Are elements in the same group similar or different?
They may have similar chemical properties, as they have the same number of outer shell electrons.
In terms of energy levels, what are the differences between elements
of the same period?
They have the same number of energy levels
The elements of Group 0 are more commonly known as…?
The noble gases
What makes the periodic table periodic?
Similar properties of elements occur at regular intervals
Elements in the same group have the same number of electrons in their outer shell; what does this tell us about their chemical properties?
They have similar chemical properties
What change in shell number is seen as one moves down a group?
The number of shells increases
How were elements organised in the early periodic table?
The strict order of atomic weights
Mendeleev overcame some problems with the table by doing
what? He also changed the order of some elements based on what?
Leaving gaps; atomic weights
The majority of elements are…?
Metals
Elements that react to form positive ions are…?
Metals
Elements that do not form positive ions are…?
Non-metals
Elements in Group 1 are known as…?
The alkali metals
State three characteristics of the Alkali Metals
All have one electron in their outer shell; have low density; are stored under oil (to prevent reactions with oxygen or water); are soft (can be cut with knife).
How do Group 1 elements react with non-metals? Why are these reactions similar for the different
Group 1 elements?
They form ionic compounds which are soluble white solids which form colourless solutions – they all have one electron in their outer shell.
How do Group 1 elements react with water?
They release hydrogen and form hydroxides which dissolve to form alkaline solutions; react vigorously with water fizzing and moving around on the surface of the water.
How does the reactivity change moving down Group 1? Why?
Reactivity increases as the atoms get larger and the distance between the nucleus and the outer electrons increases and thus attraction from the
nucleus decreases, allowing them to more easily lose electrons.
State five characteristics of Group 7
- 7 electrons in outer shell
- Coloured vapours
- Diatomic molecules
- Form ionic salts with metals
- Form molecular compounds with non-metals
State Group 7 elements and their states of matter.
- Fluorine, F. F2 is a pale yellow gas. Chlorine, Cl. Cl2 is a pale green gas. Bromine, Br. Br2 is dark brown liquid Iodine, I. I2 is a grey solid.
State three changes that occur in Group 7 as one moves down the group
- Higher relative molecular mass
- Higher melting and boiling point
- Less reactive – less easily gain electrons
