GCSE OCR C4 Chemistry Atoms, elements and the Periodic Table

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Question Answer
What does an element contain?All the same types of atoms.
What is the modern periodic table based on?The Russian chemist Dmitri Mendeleev's ideas.
What did Mendeleev do?Arranged the elements into groups and periods based on their relative atomic masses and patterns in their properties.
Why did Mendeleev leave gaps in the periodic table?For undiscovered elements and predicted properties of missing elements.
Who was Johan Dobereiner?Noticed triads that linked patterns of the relative atomic masses for three elements.
What did John Newlands notice?An octaves pattern, where every eighth element had similar properties.
What can data about properties of elements in the periodic table be used for?To work out trends and to make predictions.
What happens when elements are heated?They emit coloured flames which can be split into a line spectrum that is unique to each element.
How was helium discovered?When chemists looked at the line spectrum from the sun.
What do atoms contain?Tiny, central nucleus that contains protons and neutrons.
Where do electrons travel?Around the outside of the atoms in shells.
What do all atoms of a particular element have?The same number of protons.
How does the modern periodic table arrange atoms?In order of their proton number.
What are the number of electrons in an atom the same as?The number of protons/ the proton number.
What is the energy level like when the electron shell is close to the nucleus?Lower energy level when closer.
What are elements in Group 0 like?Full electron shells and very unreactive.
Atoms of elements with up to 3 electrons in their outer shell are called what?Metals.
Atoms of elements with 5 or more electrons in their outer shell are called what?Non-metals.
Elements with full outer shells are what?Very unreactive gases.
What is Group 1 in the periodic table called?Alkali metals.
What are the group 1 elements like?Soft metals that can be cut with a knife. Shiny surface tarnishes quickly in moist air by reacting with oxygen.
How does the reactivity change down group 1 elements?Reactivity increases as atoms get bigger.
What happens when an element from group 1 reacts with water?Hydrogen gas is formed. Also metal hydroxide, an alkali.
What are the properties of Group 1 metals?Flammable and their hydroxides are harmful and corrosive.
What is the equation for the reaction of group 1 elements with water?metal+water----> metal hydroxide+hydrogen
How do Group 1 elements react with chlorine?Sodium reacts vigorously- the reactions are faster down the group.
What is the word equation for the reaction between sodium and chlorine?sodium+chlorine----> sodium chloride
What do the halogens contain? Diatomic- two atoms joined together in each molecule.
How do the properties of the halogens change down the group?Melting points and boiling point increase but are less reactive.
When does a displacement reaction happen?When a more reactive halogen takes the place of a less reactive halogen in a compound.
What are the compounds of a group 1 element and group 7 element like?Ionic compounds- they contain charged particles or ions that are arranged in a regular pattern called a crystal lattice.
What do ionic compounds do?Conduct electricity in water when they are melted.