bonding

What is an atom mostly made up of?

Empty space

What is an atom made up of?

Nucleus (protons and neutrons) an£ electrons (in shells)

• and a lot of empty space

what is the atomic number?

and what is the atomic mass number?

atomic number (Z) : equal to number of protons in nucleus

atomic mass number (A) : equal to number of protons and neutrons in an atom

why do atoms have no net charge?

because number of protons = number of electrons = cancel out

why is an atom held together?

because of the attractive forces between the positive charged nucleus and negative charge electrons

what is an isotope?

a version of an atom that has the same number of protons but different neutrons

what is the relative atomic mass?

average mass of an atom of an element when one atom of the element carbon 12 is exactly 12

how are electr9ns distributed (generally)?

In shells, closer to nucleus = lower in energy (can’t move)- closer due to stronger forces of attraction of nucleus

what is an orbital?

an area where there is a more than 95% probability of finding an electron

how many electrons does each orbital contain?

2 electrons

what is a principle quantum number?

number beginning from closest shell to nucleus - as distance increase, area of shell increase and so shell number eg 2p6

what are valence electrons?

outermost shell electrons used for bonding - outermost orbital

what is a closed shell configuration?

and what is the aim of bonding?

max number of electrons in valence shell- completed = closed shell

aim of bonding is to get a closed shell configuration

what is Hunds rule?

when more than 1 of same orbital, electrons will go to the unoccupied orbital - decrease repulsion - reducing energy