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level: Level 1

Questions and Answers List

level questions: Level 1

QuestionAnswer
What is an atoms mass made up of?positively charged dense nucleus made of protons and neutrons negatively charged electrons are in the space outside the nucleus
What is the mass spectrometer used for?to determine the relative atomic mass of an element from isotopic composition mass: charge ratio is used atoms are bombarded with high energy electrons to produce positive ions
How is the emission spectra produced?when photons are emitted from atoms as excited electrons return to lower energy levels
What does the emission line spectrum of hydrogen provide evidence of?existence of electrons in discrete energy levels, that converge at higher energies has a series of bright lines on a dark background (line spectrum)
What is the order of energy for where electrons are found?energy level = s, p d sub-level = 1, 2, 3 orbitals
How can ion charge be calculated?no of protons - no of electrons
What are the relative masses and relative charges of the particles in an atom?proton = 1 +1 neutron = 1 0 electron= 5*10^4 -1 = mass is negligible
What is the atomic number? what letter is used to represent it?no of protons in the atom's nucleus Z
What is mass number? what letter is used to represent it?no of protons + neutrons A
How would the mass number and atomic number be placed for a symbol of an element?mass number on top (A) Atomic number (Z)
What are ions?charged particles formed when an atom loses / gains an electron
What is a positive ion + negative ion called?cation anion
What are isotopes?different atoms of the same element w different number of neutrons have the same chemical properties (React same) but diff physica properties (diff MP / BP)
Why do isotopes have the same chemical properties?they have the same no of electrons chemical reactions depend on no and arrangement of electrons
Why do isotopes have different physical properties?bec of diff masses = atom move at different speeds
What is relative atomic mass?Ar of an element is the average weighted mass of the isotope of an element when compared to the mass of 1/12th of an atom of carbon-12
What is the formula for relative atomic mass?isotope abundance * mass number / 100
What is another name for the main energy level?principal quantum number symbol = n 2n2
What is the general rule for filling the energy levels?electrons must fill from the lowest energy - highest
what does frequency equal?1/wavelength energy
What is the difference bw a line and continuous spectrum?line = only some frequencies of light can be seen continuous = all frequencies of light can be seen
How is the emission spectrum formed? (4)1) passing an electric discharge through a gas = electron gets promoted to a higher energy level ground state -> excited state 2) bec the electron is unstable in the higher level it will fall down to a lower energy level 3) this extra energy is given out as a photon of light = line in spectrum = evidence of electrons being in energy levels as the electrons can only have certain amount of energy CONC= photon of light given out from electron when it goes from high energy level = low after being excited from an electric discharge
Where do all the visible region transitions occur for the emission spectrum?when an electron falls down to level 2
Where do all the UV region transitions occur for the emission spectrum?Level 1
What happens after the convergence limit?lines merge to form a continuum after this point, electrons can have any energy
what is the order of sub-levels from smallest to biggest?s, p, d, f
What is the aufbau principle?electrons fill sub levels from lowest energy upwards = lowest possible energy
What is an orbital?region of space that has a high probability of having an electron max 2 electrons
What are the shapes of the orbitals?s = spherical p = dumbbell shape (3p orbitals are at 90 degrees to eachother d= 4 leaf clover
What are degenerate orbitals?when all the orbitals have the same energy eg: all the 3 2p orbitals
What is the pauli exclusion principle? (2)max number of electrons in an orbital is 2 if there are 2 electrons they will have opposite spin
What is Hund's rule?each electron fills each orbital separately first with the same spin = gives a lower energy and more stable
What are the 3 rules of filling out orbitals?Aufbau's principle: electrons fill out from the lowest energy level first Hund's rule: first fills out all the orbitals separately with the same spin Pauli's exclusion principle: each orbital can only have 2 electrons and they will have different spins
which transition will give the shortest wavelength in the visible region?infinity = level 2
Why is copper and chromium an exception to the aufbau principle?when half full or full shells are more stable than partially filled ones so when the difference bw energy levels is small an electron can be transferred to a higher level = more stable
What is the electron configuration for copper?1s2 2s2 2p6 3s2 3p6 4s1 3d5 this makes both the 4s and 3d sublevels half full = more stable
What is the electron configuration for Chromium?1s2 2s2 2p6 3s2 3p6 4s1 3d10 a full 3d shell is more stable