The Periodic Table *DOUBLE* Flashcards
Which type of substance is found in the periodic table, elements, compounds or mixtures?
elements
What is a vertical column in the periodic table called?
group
What is a horizontal row in the periodic table called?
period
How are elements in the periodic table arranged?
in order of atomic number
What do elements in the same group have in common with each other?
same number of outer shell electrons and therefore similar properties
Why is the periodic table called the periodic table?
similar properties occur at regular intervals
In which group will you find elements with one outer shell electron
group 1
In which group will you find elements with seven outer shell electrons?
group 7
How were early versions of the periodic table arranged?
in order of atomic weight
What was the problem with arranging elements in order of atomic weight in early versions of the periodic table?
some elements were in inappropriate groups, they didn’t share similar properties.
Name the Russian chemist who developed the periodic table in 1869, on which the modern day periodic table is based.
Mendeleev/Dmitri Mendeleev
What did Mendeleev do to overcome problems of early versions of the periodic table?
he left gaps for elements he thought had not been discovered and in some places changed the order based on atomic weights.
How did Mendeleevs periodic table gain acceptance?
elements predicted by Mendeleev were discovered and filled gaps he had left on the periodic table, and knowledge of isotopes explained why ordering in terms of atomic weight wasn’t always correct.
What do we use to compare the masses of atoms of different elements?
relative atomic masses
In general, what is a scientific prediction?
what you think will happen and why you think this
About how many elements are there in the modern periodic table?
about 100, specifically 118
Where are the non-metals placed in the modern periodic table?
right-hand side/top right
Where are metals found in the modern periodic table?
left-hand side
Are the majority of elements metals or non-metals?
metals
Define metals in terms of the ions they form when they react.
Elements that react to form positive ions are metals.
Define non-metals in terms of ions they form when they react.
Elements that react to form negative ions are non-metals.
Sodium atoms have 11 electrons. How many protons do they have?
11
What do atomic numbers tell you about an atom?
the number of protons in the nucleus
Where are elements with similar properties placed in the periodic table?
in groups/columns
Where do the atomic numbers increase by 1 each time in the periodic table?
in a period
Where are the electron shells / energy levels found in an atom?
around the nucleus
What are the elements in group 0 of the periodic table called?
noble gases
Why are group 0 elements unreactive?
their atoms have a stable arrangement of electrons (full outer shells)
How many electrons do noble gases have on their outer shell?
eight, except for helium which has only two electrons.
Describe the trend in boling points of noble gases.
the boiling points of noble gases increase with increasing relative atomic mass (going down the group).
Name a group 0 element.
helium/neon/argon/krypton/xenon/radon
What are the elements in Group 1 of the periodic table called?
alkali metals
What gives the alkali metals their characteristic properties?
single outer shell electron
Describe how reactivity of the group 1 elements changes going down the group.
the reactivity of group 1 elements increases down the group
Describe the properties of the alkali metals.
soft (can cut), low density (float on water), low melting and boiling points, reactive.
Describe the reaction of lithium, sodium and potassium with oxygen.
React with oxygen in air to form metal oxides, the silvery shiny surface of the metal quickly goes dull as it reacts with oxygen in air.
Describe the reaction of lithium, sodium and potassium with chlorine.
React with chlorine to produce ionic compounds, metal chlorides, which are white solids. An example of this is sodium chloride which is table salt. Metal chlorides are all soluble in water.
Describe the reaction of lithium, sodium and potassium with water.
React with water to form metal hydroxide (alkali, turns universal indicator purple) and hydrogen gas (fizzing). Move around on top of water as they react and can burst in to flame (sodium = orange flame, potassium = lilac flame)
What are the elements in Group 7 of the periodic table called?
halogens
What is a halide?
a chemical compound in which one element is a halogen
The atomic number of chlorine is 17. How many electrons do its atoms have?
17
Why do Group 7 elements have similar reactions?
they all have seen electrons in their outer shell
Are group 7 elements metals or non-metals?
they are all non-metals
Do the group 7 elements exist as single atoms or molecules?
all group 7 elements exist as molecules - pairs of atoms eg Cl2, Br2. They are called diatomic molecules.
What is formed when halogens react with metals?
halogens react with metals to form ionic compounds called metal halides, for example fluorine + sodium –> sodium fluoride
What is formed when halogens react with hydrogen?
halogens react with hydrogen to form hydrogen halides, for example fluorine + hydrogen –> hydrogen fluoride
How does the reactivity of group 7 elements change going down the group.
the reactivity of group 7 elements decreases going down the group.
Describe displacement in terms of halogens.
A more reactive halogen can displace a less reactive halogen from an aqueous solution of it’s salt, for example chlorine can displace bromine from an aqueous solution of sodium bromide.
Describe the change in relative molecular mass of group 7 elements as you go down the group
relative molecular mass increases down the group
Describe the change in melting and boiling points of group 7 elements as you go down the group.
melting and boiling points increase as you go down the group. This is why flourine and chlorine are gas at room temperture, bromine is liquid and iodine is solid.
Explain why reactivity increases going down group 1.
As you go down group 1, the outer electron gets further away from the attraction of the positive nucleus and the additonal electron shells shield the electron from the nucleus. These factors combine to make it easier for elements lower down the group to react by losing the outer electron.
Explain why reactivity decreases going down group 7.
As you go down group 7, the outer electron shell is further away from the attraction of the positive nucleus and the additonal electron shells shield the electron shell from the nucleus. These factors combine to make it harder for elements lower down the group to react by gaining an electron.
