Chapter 2 The Periodic Table Flashcards
How are elements arranged in the periodic table?
Elements are arranged in the order of their atomic number in the periodic table.
Where can you find an element’s atomic number on the periodic table?
The atomic number is the smaller number shown alongside the element’s symbol in the periodic table.
How did John Newlands order the elements in the early periodic table?
John Newlands first proposed a type of periodic table in which the elements were placed in order of atomic mass.
What observation did John Newlands make with respect to the properties of elements and their order in the periodic table? What was this observation called?
John Newlands observed similar properties in every 8th element until calcium. This was called the “Law of Octaves”.
How was Mendeleev’s periodic table different from Newlands’?
Dimitri Mendeleev (1869) then reordered the periodic table to leave gaps where he predicted that undiscovered elements should be.
What do we call the columns in the modern periodic table?
In the modern periodic table elements with similar properties are arranged in columns called groups.
What does the group an element is in tell us about the number of elements in its outer shell?
Elements in the same group have the same number of electrons in their outer shell.
How many electrons are there in the outer shell of elements in each group of the periodic table?
The group number indicates the number of electrons in the outer shell.
What does the number of electrons in the outer shell of an atom determine?
The number of electrons in the outer shell determines the chemical properties of an element.
What are the names of Group 1, Group 2, Group 7 and Group 8.
Group 1 elements are called the Alkali Metals, Group 2 are called the Alkaline Earth Metals, Group 7 are called the Halogens and Group 8 are called the Noble Gases.
How are metals and non-metals organised in the modern periodic table?
In the modern periodic table, metals are to the right and non-metals are to the left.
What do we call the rows in the periodic table?
The rows in the periodic table are called periods.
What additional knowledge was used to decide to order elements by atomic number instead of atomic mass?
Knowledge of isotopes explained why ordering the elements by mass is not always accurate so modern periodic tables order elements by atomic number.
What information does the atomic number give?
The atomic number is the number of protons in an atom.
What are ions?
Ions are atoms that have different numbers of protons and electrons. Ions are charged atoms.
What is produced when an atom gains an electron?
Atoms that gain electrons become negatively charged ions.
Example: Cl-
What is produced when an atom loses an electron?
Atoms that lose electrons become positively charged ions.
Example: Na+
What type of ions do metals always make? Why?
Metals are elements that form positive ions because they lose electrons to achieve a full outer shell to become stable.
What type of ions do nonmetals always make? Why?
Non-metals form negative ions because they gain electrons to get a full outer shell to become stable.
Describe the outer shell of noble gases.
The noble gases all have a full outer shell of electrons.
What happens to melting and boiling points of alkali metals as you move down the group?
As you move down the group 1 Alkali metals in the periodic table the melting and boiling points of the metal decrease.
Explain why potassium is more reactive than lithium.
The outer electron in potassium is further away from the positively charged nucleus than the outer electron in lithium is. This means it is held with less force so is easier to lose. This makes potassium more reactive than lithium.
What type of bonds do halogens form when they react with non-metals? What does this involve?
When halogens react with nonmetals they form covalent bonds where they share electrons to achieve full outer shells.
What happens to the melting and boiling points of Halogens as you move down the group?
As you go down the group the properties of halogens show trends. The melting and boiling points increase.
What happens to the reactivity of Halogens as you go down the group? How does this compare to the trend with the Alkali metals?
As you go down the group the reactivity of Halogens decreases, This is opposite to what happens with the Alkali metals.
Explain why the reactivity of the Halogens decreases as you go down the group.
The reason that the reactivity of Halogens decreases is because the number of shells of electrons increases down the group, so larger elements attract electrons from other atoms less, so can’t react as easily.
What happens when a more reactive Halogen is placed in a salt of a less reactive Halogen?
More reactive halogens displace less reactive halogens from a solution of its salt.
Where are the Transition metals found on the periodic table?
The transition metals are between Groups 2 and 3 in the periodic table and have similar properties.
What additional property do the ions of transition metals often have?
Ions of transition metals are often coloured.
