Periodicity Flashcards
1
Q
How is the periodic table arranged?
A
- arranged in order of increasing proton (atomic) number
2
Q
What are the block of metals in between groups ll and lll known as?
A
- transition elements
3
Q
What is a metalloid defined as?
A
- elements that have the properties of both metals and non-metals
4
Q
What are some examples of metalloids?
A
- silicon (Si)
- germanium (Ge)
5
Q
What is the relationship between the valence electrons and their group number?
A
- an element has the same number of valence electrons and group number
- e.g. carbon (group: IV) (no. of valence electrons: 4)
6
Q
What is the relationship between the number of electronic shells and the period number?
A
- an element has the same number of electronic shells and period number
- e.g. silicon (period: 3) (electronic configuration: 2.8.4)
7
Q
How does the number of valence electrons change across the period?
A
- increases progressively by 1
- e.g. Na (2.8.1), Mg (2.8.2), Al (2.8.3)
8
Q
What properties of the elements changes across the group?
A
- chemical properties
9
Q
Why do the chemical properties of the elements change across the group?
A
- the number of valence electrons increasing across the period
