Periodic table Flashcards
What was in Mendeleev proposed periodic table
He listed the elements in order of increasing atomic mass (or weight as it was known then) but he was prepared to slightly alter the order of the elements if he felt the properties of the element fitted a different position;
He left gaps for undiscovered elements and predicted the properties of these elements; for example, the properties of germanium, when it was discovered, were very similar to what he had predicted.
What is in the modern periodic table
- Elements are arranged in order of atomic number, rather than atomic mass,
- Noble gases are present;
- There are no gaps and there are more elements;
- There is a block of transition metals;
- There is a block of actinides and lathanides.
What is in both Mendeleev periodic table and modern periodic table
they both placed the known elements in order
What is an element
An element is a substance which consists of only one type of atom. Elements can’t be broken down into anything simpler substance by chemical means.
What are elements classified as
Metals and Non-metals
What are Metals and what are the properties of them
Metals are to the left of the staircase line on the Periodic Table and are malleable (can be hammered into shape), ductile (can be drawn into wires), sonorous (make a ringing sound when struck), good conductors of heat and electricity and have high melting points
What are the gases, liquids and solids in the periodic table
Two elements in the Periodic Table are liquids at room temperature and pressure (mercury and bromine), there are 11 gases including the six noble gases, fluorine, chlorine, hydrogen, oxygen and nitrogen, and the rest of the elements are solid at room temperature and pressure.
What is a period
It is an Horizontal row in the periodic table
What is a group
It is an vertical column in the periodic table
What are group 1 known as
It is a group of reactive metals and the group is known as alkali metals
What are group 2 known as
It is a group of reactive metals and the group is known as alkaline-earth metals
What are group 7 known as
It is a group of reactive non-metals and the group is known as halogens
What are group 8 known as
It is a group of reactive non-metals and the group is known as noble gases
What is Group 1 Alkali Metals stored in and why
They are stored under oil to prevent them from reacting with air or water vapor in the air.
Properties of group 1 Alkali Metals
are soft and are easily cut with a knife,
are shiny when freshly cut but tarnish (go dull) rapidly when exposed to air;
have low density and the first three - lithium, sodium and potassium are less dense than water, and float on the surface of water;
are grey solids which have relatively low melting points. The melting points decrease as the atoms get bigger going down the group.
Reactivity of group 1 Alkali Metals
Reactivity increases down the group
All of the atoms of Group 1 elements have one electron in their outer shell which they lose when the elements react to form a positive ion with full electron shells; as the outer electron is further from the nucleus as Group 1 is descended the elements become more reactive as the outer electron is lost more readily
Reaction equation for group 1 Alkali Metals with water
Group 1 metal + water → metal hydroxide + hydrogen
Colour of group 7 Halogens
Fluorine → Yellow
Chlorine → yellow-green
Bromine → red-brown
Iodine → grey-black
Astatine → black solid
What is the state of the Halogens at room temperature
Fluorine → gas
Chlorine → gas
Bromine → liquid
Iodine → solid
Astatine → solid
Iodine sublimes What does that mean
When heated and changes from a grey-black solid to a purple vapor. (changes from solid to gas)
Reactivity of group 7 Halogens
Reactivity decreases down the group
All of the atoms of Group 7 (VII) elements have seven electrons in their outer shell and so they gain one electron when the elements react to form a negative ion with a full outer shell.
Further down the group, the atoms have more shells of electrons, so the outermost shell containing electrons is further from the positive attraction of the nucleus. This means the force of attraction between the positive nucleus and an incoming electron decreases and they are less reactive. Also there are more electron shells between the outer electron and the nucleus and these inner electrons shield the outer electron from the attractive power of the nucleus.
What is displacement reactions
A more reactive halogen displaces a less reactive halogen from solution.
Chlorine is more reactive than iodine so chlorine can displace it from potassium iodide solution forming iodine and potassium chloride.
Word equation: chlorine + potassium iodide iodine + potassium chloride
Symbol equation: Cl₂ + 2KI → l₂ + 2KCl
ionic equation: Cl₂ + 2I → I₂ +2Cl-
Properties of The Transition metals
they have higher melting points;
they have higher density;
they are less reactive with water,
they react and form ions with different charges, but Group 1 metals only form 1+ ions.
What colour are some of the Transition metals
copper(II) oxide is black
Copper(II) Carbonate is green
hydrated copper (II) Sulfate is blue
copper (II) Salts are usually blue in solution
Properties of the group 0 Noble gases
The noble gases are a group of unreactive non-metals.
Their lack of reactivity is due to the atoms of each element in the group having a full outer shell of electrons.
All of the elements in the group are colourless gases at room temperature and exist as individual atoms.
As the group is descended the boiling points of the elements increase due to the increased strength of the van der Waals’ forces between the atoms.
