Chemistry Flashcards
Periodic table was devised by ____ in 1869
Dmitri Mendeleev (1834-1907) a Russian chemist
Groups are represented by ____ on the periodic table
Columns
Periods are represented by ____ on the periodic table
Rows
Chemical reactivity
the ability to form chemical bonds with other atoms
the weighted average for an elements’ naturally occurring isotopes on earth
An elements atomic mass is
The Bohr model shows the atom as
having a central nucleus containing protons and neutrons, with the electrons in circular shells around the nucleus
Electron shells closer to the nucleus have _ energy
lower
Groups and periods are arranged on the periodic table in order to show an element’s
physical state at room temperature and its chemical reactivity
An early model of the atom was developed by ___ in 1913
Niels Bohr (1885–1962) a Danish scientist
Differences in chemical reactivity between elements are based on
the number and spatial distribution of their electrons
In order to move between shells, an electron must absorb or release an amount of energy corresponding ____
exactly to the difference in energy between the shells
If two atoms have ____, they can react and form a chemical bond, creating a ____
complementary electron patterns, molecule or compound
when an excited electron drops back down to a lower-energy shell, it will release energy, often in the form of ___
heat
The atomic number shows how many ___ an element has
protons
The Bohr model is useful to explain the _____ and _____ of many elements
reactivity , chemical bonding
Electron orbitals are
regions of space around the nucleus where electrons spend most of their time
s subshells have what kind of shape?
single, spherical orbital
p subshells have what kind of shape?
three dumbbell-shaped orbitals at right angles to each other
s and p subshells are most important to be familiar with because
most of organic chemistry involves interactions between electrons in those subshells
d and f subshells are more complex and have how many orbitals
5 - 7
In the Bohr model, electron shell __ corresponds with 1s orbitals
1n
the ___ orbital is the closest to the nucleus
1s
What orbital gets filled first with electrons?
1s
How would you show Hydrogen in electron configuration?
1s^1
Each row on the periodic table of elements reperesents
the filling of a different electron shell
on the periodic table of elements, a column number gives info about number of ____ and ____
valence electrons and reactivity
the valence electrons of elements in a certain column on the periodic table of elements are ____
equal
group number is a good predictor of
how reactive an element may be
elements that satisfy the octet rule are
less reactive
non-reactive elements are called
inert gases or noble gases
group 18 on the periodic table of elements are called
inert or noble gases
unstable atoms can become more stable by
losing or sharing a valence electron
elements that fully lose an electrons become
positively charged ions
group 17 elements that have 7 electrons in their outer shell tend to achieve a stable octet by
taking electrons from other atoms
when an element takes an electron from other atoms, they become
negatively charged ions
If there is an even number of electrons in the outer shell of an atom, those elements tend to achieve a complete valence shell by
forming bonds with multiple other atoms
The 2n shell of the Bohr model has what kind of electron orbitals
one spherical s orbital and three dumbbell shaped p orbitals
Each orbital in the 2n shell can hold how many electrons?
2
Electrons will fill what kind of orbital first?
s
Elements in the second row of the periodic table place their electrons in what shells?
2n and 1n
Third-row elements on the periodic table place their electrons in what orbitals/shell?
s and 3-p orbitals/3n
Why does the d orbital of the 3n shell not begin to fill until the fourth row of the periodic table?
It is considerably higher in energy than the 3s and 3p orbitals
Aufbau means ____ in german
building
What are the three “blocks” on the periodic table?
s, d, and p
Why do electron configuration models go from 2s to 2p instead of 2s to 1p?
The P “dumbbell” shape is not needed for the first shell. By using quantum numbers we see that the first shell only has one orbital and that will defer to the sphere shape and thus it will be 1s
If each electron orbital can hold 2 electrons, how is it possible to have 2p^6 for an electron configuration?
The second shell can fit 6 electrons
In the following elements, there is 1 electron, not the predicted 2, in the outermost s subshell, the “missing” electron is instead located in the outermost d subshell:
Cu, Cr, Nb, Mo, Ru, Rh, Ag, Pt, Au
In Pd (palladium) configuration is
[Kr] 4d¹⁰ (the 5s is empty).
All the other exceptions are in the f block. Here are the f-block exceptions:
La, Ce, Gd, Ac, Th, Pa, U, Np, Cm, Lr
Z-effective is high on the right side of the periodic table of elements because
The d orbital can hold how many electrons?
10
How can you tell how many core electrons an element has?
How can you tell how many valence electrons an element has?
by group # on periodic table
Ionization energy is
the energy required for an atom to lose electrons
Electron affinity is
the tendency for an atom to attract electrons
Electronegativity is
the tendency for an atom to hog electrons over lending them when atomic bonds are being made
True or false : the noble gases don’t like to gain or lose an electron
True
In a neutral atom # of protons matches # of electrons
Can you find the percent chlorine by mass for compounds containing chlorine?
Yes, I need the molar masses of each element in the compound. I then need to divide the molar mass of chlorine by the total molar mass of the compound.
In a water molecule, why is there a partial negative charge on the oxygen side and positive on the hydrogen?
Electronegativity of oxygen causes there to be a more negative charge due to its tendency to hog electrons. There is a positive charge around hydrogen as the electrons are being pulled closer to the oxygen side.
Photoelectric effect can be used to calculate energy of electrons by
If we know the kinetic energy of the ejected electrons (known as photoelectrons) and the energy of the incident radiation, we can calculate the energy of the electrons in the solid metal
