Properties of Elements and Chemical Bonds Flashcards
What is periodic law?
when elements are arranged in order of increasing atomic number, elements with similar chemical properties occur at period intervals
What is the difference between period and group?
Period - HORIZONTAL ROW, 1-7
Group - VERTICAL, 2 groups subdivided into A and B
Metal vs Non-metal
Metal (left side of table) - lustre, thermal and electrical conductivity, malleability, ductile, solid at room temp, high melting points Groups 3-12 (give electrons)
Non-metal (right sight of table) - opposite, zig zag dividing line (takes electrons)
What are valence electrons?
Number of electrons in the outer most shell
Elements in same group = same number of valence electrons (group number)
What are Lewis symbols?
Electron dot symbols, equal to number of valence electrons in atom
What is chemical bonding?
Attractive force that holds two atoms together in a more complex unit
What is an ion?
An ion that is electronically charged as a result of the loss or gain of electrons
Atom GAINS - negatively charged (electrons outnumber protons)
Atom LOSES - positively charged (more protons than electrons)
Rules for writing chemical symbols for ions
Subscript place to right of chemical symbol
Number precedes the charge sign
Single - or + to denote charge of 1
What is an ionic bond?
Chemical bond formed through transfer of one or more electrons from one atom or group of atoms, to another atom or group of atoms.
One gives, one takes. Forms when atoms are held together by the attraction between opposite charges
Electron loss/gain that involves fewest electrons will always be the most favourable process.
What is an ionic compound?
Compound where ionic bonds are present.
Binary ionic compounds - one element is metal the other is nonmetal
What is a polyatomic ion?
A tightly bonded group of atoms with a positive or negative charge.
Very stable, charged pieces of compounds (not compounds themselves)
Most carry negative charge and oxygen atom
What is a covalent bond?
Chemical bond formed through the sharing of one or more pairs of electrons between two atoms equally
Forms when atoms share electrons to satisfy the octet Ryle
How can a polar covalent bond have a partial charge?
The more electronegative atom attracts the shared electrons more strongly - acquires a partial negative charge
The less electronegative one acquires a partial positive charge
What is a non polar vs polar covalent bond
Polar - shares electrons unequally, one side has more density
Non-polar - shared equally
