Structure and Bonding Flashcards
(16 cards)
What are the 3 types of chemical bonding?
Ionic
Covalent
Metallic
What are chemical compounds?
They form when atoms bond by ionic or covalent bonding
What is ionic bonding
Ionic bonding occurs between a metal and non metal. The metal transfers valence electrons to the non metal. the metal atom form posisitve ions called cations and the non metalatoms form negative ions called anions.
What is the crystalline structure of ionic compounds?
At room temperature ionic compounds exist as crystalline solids. They have strong electrostatic forces of attraction betweent the ionds known as ionic bonds that hold the oppositely charged ions together in a regualr,repeating 3D arrangement through the crystal. (crystal lattice)
What is covalent bonding.
Covalent bonding occurs when two or more non metal atoms bond. Unpaired valence electrons are shared between the atoms forming molecules.
What happens with the electrons shared in covalent bonding?
They orbit around the atoms sharing them. This forms strong covalent bonds which hold the atoms together.
What are the types of covalent bonds?
single bond
triple bond
double bond
What is the structure of covalent compounds?
they consist of individual molecules which can be polar or non polar depending on the elctronegativity of the atoms present.
What is electronegativity?
The measure of how strongly atoms attract bonding electrons
What are the most electro negative elements?
chlorine
oxygen
nitrogen
flourine
What happens in a polar molecule(covalent bond)?
In a polar moelcule on atom has a partially negative charge and one has a partially positive charge. This is because the atoms at either side of the covalent bond attract the electrons at different strengths.
What are some examples of polar molecules?
water
hydrogen chloride
ammonia
What happens in a non polar molecule?
The electronegativity of the atoms are similar or thr same and they attract the electrons with the same strengh so they dont have any partially charger atoms.
What are some examples of non polar molecules?
hydrogen- h^2
oxygen- o^2
What is metallic bonding?
Metallic bonding occurs in metals. The metal atoms are packed closely together in a metal lattice and the valence electrons become delocalised. This means that the valence electrons are no longer associated with a specific atom and can move freely. This forms positive cations called the ‘sea of electrons’.
