Chemistry Chapter 4
Most elements are ______.
metals
The ______ include all members of Groups 1-12 as well as some elements of Groups ___ through ___.
metals, 13, 16
93 elements come from ____ and are _____ produced while the other 113 are ____ and are made by _____.
nature, naturally, synthetic, scientists.
The ________ are very stable and have low reactivity.
noble gases
The ___________ have a full set of electrons in their outermost energy level.
noble gases
The ________ include all of the elements in Groups 17-18 as well as some members of Groups ___ - ___.
non-metals, 13, 16
The special equiptment that scientists use to create elements are called ______________.
particle accelerators
A period is a ___ of bloack in the periodic table.
row
When a massive star has converted almost all its core hydrogen and helium into heavier elements, it collapses and blows apart in an explosion called a _______ forming elements heavier than iron.
supernova
Elements that chemists have created are called _____ elements.
synthetic
In general, the _________ are metals that are less reactive than the alkaili metals and the alkaline earth metals.
transition metals
Unlike the main-group elements, each group of the ________ does not have the identical outer electron configuration.
transition metals
The nuclear reaction that changes one nucleus into another by radioactive disintegration or by bombardment with other particles is called _______.
transmutation
The production of synthetic elements is an example of a type of nuclear reaction that is called ____.
transmutation
Why do elements with similar properties appear at regular intervals in the periodic table?
Because the Periodic Law states that when elements are sorted by atomic number, elements with similar properties appear at regular intervals.
Which of the following elements has the largest electronegativity: lithium, carbon, chlorine, or iodine?
Chlorine
Explain the large decrease in atomicc radii as you move across a period from Group 1-14...
The outermost electrons are pulled closer to the nucleus and to each other. There is finally a point where the electrons can't move closer to the nucleus because they are to close to each other. Electron shielding also doesn't play a role as you move across a period.
How is the electron configuration similar for each element in a period?
The same number of energy levels are filled. For example in Period four all of the elements start with 4_^_.
What is unique about the nuclei of all elements of the actinide series?
Their nuclei are more important than their electron configurations because they are very unstable and spontanuosly burst apart.
How did Dmitri Mendeleev use to arrange the periodic table?
He arranged them by their atomic weights, because similar properties would then repeat in regular intervals.
Why did Mendeleev leave gaps in the table?
He predicted the properties for elements that haven't been found yet, and figured that later on they would eventually be discovered.
How did Henry Moseley contribute to the periodic table?
He studied the lines in the x-ray spectra of 38 different elements and found that the wavelengths of the lines decreased as the atomic masses increased. It was his idea to organize elements by their atomic numbers.
How did John Newlands organize the elements?
He used the law of octaves, which said that every 8 elements have similar chemical properties and they repeat in every row.
Why is a helium atmosphere used in welding instead of an oxygen rich one?
Helium doesn't react and it isn't very flamable, whereas oxygen reacts with a lot of things, and feeds fires.
As the nuclear charge increases across a period, the effective nuclear charge _____ pulling the electrons closer to the nucleus and ____ the size of an atom.
Increases, decreases
Which of the following elements has the largest atomic radius: boron, aluminum, gallium, or indium?
Indium
What is the trend for atomic radius?
It decreases across a period and increases down a group.
What is the trend for ionic size?
It decreases across a period and increases down a group.
What is the trend for electronegativity?
It increases across a period and decreases down a group.
What is the trend of ionization energy?
It increases across a period and decreases down a group.
How does a synchrotron accelerate particles to create synthetic elements?
It times pulses as it accelerates and matches the acceleration of the particles.
A metal can be squeezed out into a wire it is ___.
Mallaeble
Why was Moseley able to resolve the discrepancies in Mendeleev's table when Medeleev could not?
Mendeleev couldn't figure out a way to organize elements since they never fit neatly when sorted by atomic mass. Moseley sorted them atomic numbers and found them to arrange very nicely.
What is the difficulty in identifying superheavy elements?
Most superheavy elements only exist for a tiny fraction of a second.
Which metal has a larger radius, Li or Na? Why?
Na, because atomic radii increase as you move down a group, and Na is lower in the group than Li is.
Which of the following elements has the smallest ionization energy: potassium, arsenic, nitrogen, or bismuth?
Potassium
Properties of Actinides?
Radioactive and very reactive and also very unstable. Col. 3-12.
Properties of Hydrogen?
Reacts with almost everything. Has one valence electron. Ends in s1. Col. 1.
What are the characteristics of transition metals?
Somewhat reactive and some seldom form compounds with other elements. They are ductile and malleable and make good conductors. They do not similarly end in anything. Col. 3-12.
How is the elecrton configuration similar for each element in a group?
The ending sublevel is always the same. For example Group 1 would always end in ___s^1.
What are the characteristics of halogens?
The most reactive group of non-metals. When they react with metals, they usually produce salts. They can be both gases and solids. They are usually found in sea water and in rocks in earth's crust. They end in p5. Col. 17.
Why are there limits to the synthetic elements that a cyclotron can produce?
There is a limit to the energues that can be reached so there is a limit to the elements that can be made.
Why do Li, Na, K, Rb, Cs, and Fr all react with Cl in a 1:1 ratio forming substances with similar properties?
They are all in the same group, meaning that their chemical properties are similar and they all react with things similarly.
What are the characteristics of alkaline earth metals?
They are highly reactive and are usually found as compounds. They are very hard and have a high melting point.They end in s2. Col. 2
What are the characteristic of noble gases?
They are not reactive and have full valence electrons. They are gases and are not very flammable.They end in p6. Col. 18.
Properties of Lanthanides?
They are shiny and are similar to the alkaline earth metals in terms of reactiveness.Col. 3-12.
Using electron configuration, explain why the halogens readily react with the alkali metals to form salts...
They easily lose valence electrons and form compounds such as sodium chloride.
Why are Group 2 elements less reactive than Group 1 elements?
They have 2 valence electrons and must lose both to become stable.
Why are the main-group elements called the representative elements?
They have a wide range of properties.
What are the characteristics of alkali metals?
They mix with water to make alkaline solutions. They are highly reactive and are never found in nature as pure elements. They can be solf and easily cut. They are usually shiny but can dull quickly. They are good conductors of electricity. They also end in s1. Col. 1
Why is an iron alloy, such as steel, preferred over pure iron?
They tend to be harder, stronger, and more resistant to corrosion.
Why are valence elecrtons important?
Valence electrons participate in chemical reaction and elements with the same number of valence electrons react similarly.
In the __________, electrons are being added to the 5f orbitals.
actinides
The ________ are unique in that all are unstable and radioactive.
actinides
The ______ have a single electron in the highest occupied energy level.
alkali metals
The _______ are metals that lose one electron when they react with water to from alkaline solutions.
alkali metals
All the __________ have two valence electrons and get to a stable electron configuration by losing two electrons.
alkaline earth metals
In the sun, the fusion of two helium nuclei produces a nucleus of the element ____ and the release of energy in the form of gamma radiation.
beryllium
The currently most-accepted scientific model of the universe's beginnings is an explosion called the ___.
big bang
The _______ is half the distance from center to center of two like atoms bonded together.
bond radius
Most of the atoms in living things come from just six elements...they are:
carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur
The effect that causes the outermost electrons in an atom or ion to be held less tightly to the nucleus because of inner electrons is called ____.
electron shielding
Immediately after the big bang, temperatures were extremely high and only ________ could exist.
energy
Massive atoms such as iron and nickel form by repeated ______.
fusion reactions
Elements in a ___ in the periodic table can be expected to have similar properies.
group/collumn
The ______ are highly reactive and readily for slats with metals.
halogens
The ________, the most reactive group of non-metals, achieve stable electron configurations by gaining one electron.
halogens
The temperatures in stars get high enough to fuse ____ nuclei with one another, forming elements of still higher atomic numbers.
helium
With its one valence electron, _______ reacts with many other elements.
hydrogen
As the universe continued to cool, these particles joined and formed the first two elements, ______ and _____.
hydrogen and helium
The amount of energy needed to remove an electron from a specific atom is called the _______ energy of the atom.
ionization
In the __________, electrons are being added to the 4f orbitals.
lanthanides
A span of thirty seconds is considered a ____ time for the existance of a superheavy element.
long life
The _________ are in the s- and p-blocks of the periodic table.
main-group elements
A synchrotron can accelerate charged particles to high speeds because it compensates for the increase in the particle's ____ because of the increase in the particle's energy.
mass
All elements in the periodic table with atomic numbers greater than that of the element ___ are formed by the explosions of collapsing stars.
106
When did Newland contribute to the periodic table?
1865
When did Mendeleev contribute to the periodic table?
1869
Elements in Groups ___ through ___, including the two long rows below the table, are called transition elements.
3, 12
Why is helium a noble gas?
A Noble Gas does not need to have eight electrons to be classed as such - it simply must have a full outer shell. The first shell can only hold two electrons, which is what helium has, so helium is a Noble Gas. The second and third shells hold eight electrons, which is why other noble gases can be seen as having eight electrons. However no Noble Gases have eight electrons in total - just eight in the outer shell, as the shells fill from the inside out...
Which groups compose the main-group elements?
Alkali metals, Alkaline earth metals, halogens, and noble gases.
Explain why the exact size of an atom is difficult to determine?
An atom's size depends on the volume occupied by the electrons around the nucleus and the electrons don't move in well-defined paths.
In the transition elements, electrons are usually added to the _____ orbital, which is why these elements are also known as the _______.
D, d-block elements
The development of the first successful periodic table is credited to...
Dmitri Mendeleev
What are the properties of most metals?
Ductile, Malleable and Conductive of heat/ electricity
_______ is the energy change that occurs whena neutral atom gains an electron.
Electron affinity
Explain the large increase in electronegativity as you move across a period...
Electron shielding doesn't occur as you move across a period so nuclear charges increase across a period which increase electronegativity.
__________ is a numerical value that reflects how much an atom in a molecule attracts electrons.
Electronegativity
Explain why ionization energies tend to decrease as you move down a group...
Elements down a group occupy more energy levels, therefore the outermost electrons are farther from the nucleus which causes a bigger pull.
As the As the universe began to cool, energy was converted to ____, in the form of _____, ______, and _____.
matter, electrons, protons, neutrons
