Topic 3 Flashcards
What two factors cause the outer electrons to not experience the full nuclear charge?
Shielding and Repulsion
What is Nuclear Charge?
Atomic Number
What is the trend for effective nuclear charge across a period?
The effective nuclear charge increases because the number of shielding electrons remains the same, but the atomic nuclear charge increases.
What is the trend for effective nuclear charge down a group?
The effective nuclear charge remains the same because the nuclear charge and shielding electrons both increase by 8, they “cancel” change out.
How do we find atomic radius?
Atomic radius is half the distance between the nuclei of neighboring atoms
*Must be solved this way because electrons are in orbitals and their exact location is unknown
Cations are (smaller/larger) than their atoms
Smaller
Anions are (smaller/larger) than their atoms
Larger
Electron affinity
A measure in the change in energy when 1 mole of electrons is added to 1 mole of gaseous atoms to form gaseous ions
When the first electron is added in electron affinity, is the reaction endothermic or exothermic?
Exothermic
When does electron affinity become an endothermic process?
When a second electron is added because the anion and second electron repel
How do you find the effective nuclear charge?
Atomic number - number of nonvalence electrons
Electronegativity
A measure of an element’s attraction for an electron in a covalent bond/a bonding pair of electrons
Down group 1, do melting points increase or decrease? Explain why.
Melting points decrease because the atomic radius increases which makes it harder for the metallic bonds to reach the electrons in other atoms, so the IMFs are weaker, and it takes less energy to melt
Down group 17, do melting points increase or decrease? Explain why.
Melting points increase because atomic radius increases, so the strength of the temporary dipoles in London dispersion forces increases, so the IMFs are stronger, and it takes more energy to melt
Group 17s are diatomic, when size of molecules increases, LDFs increase
Metalloids and macromolecules (network solids) have ____ melting points
Very High
Metals have ____ melting points
High
Nonmetals have ____ melting points
Low
Noble gases have ____ melting points
Very Low
Does reactivity for metals increase as you go up or down the groups?
Down
Does reactivity for nonmetals increase as you go up or down the groups?
Up
Group 1 metals react with halogens to form what?
Ionic Salts
What do group 1 metals form when they react with water?
A base and hydrogen gas
When a group 1 reacts with water is the reaction endothermic or exothermic?
Exothermic
Metal oxides are (acidic/basic)
Basic