Periodic Trends - Final Complete
Describe the trend of the atomic radius in the periodic table.
Atomic radius generally decreases from left to right across a period, although there are some small exceptions to this trend, such as the relative radii of oxygen and nitrogen
Identify each physical property as more characteristic of a metal or of a nonmetal. luster malleability brittle texture low melting point good conductor of electric current
luster - metal malleability - metal Brittle texture - non metal low melting point - non metal good conductor of electric current - metal
What is electronic shielding. Explain shielding in relationship to ionization energy and periodic trends.
the inner electron shield the outermost electrons from the full effect of the positive charge of the nucleus. Shielding actually reduces ionization energy. The shielding effect explains why valence-shell electrons are more easily removed from the atom. The effect also explains atomic size. The more shielding, the further the valence shell can spread out and the bigger atoms will be.
The chemical properties of various elements are intimately related to their
valence electron configurations.
What happens to the ionic radius when you remove an electron (cation)?
A cation (green) that is smaller than the parent atom because the remaining electrons are drawn closer to the nucleus because the protons now outnumber the electrons. Also if all valence electrons are removed the ion has fewer occupied principal energy levels to the electron cloud is smaller.
Characteristics of a metalloid
A metalloid is an element with properties that are intermediate between those of metals and nonmetals. Metalloids are: metallic-looking brittle solids; malleable; either semiconductors or exist in semiconducting forms; and have weakly acidic oxides.
What is a trend?
A trend is a general increase or decrease in a particular measurable quantity an overall direction
What are alkali metals?
Alkali metal are the elements in Group 1 of the s block. They have a single s electron in their outermost principal energy. They are highly reactive. Reactions between alkali metals and water are vigorous and include production of large quantities of hydrogen gas. Alkali metals react easily with most nonmetals. All of the alkali metals are too reactive to be found in nature in their pure elemental form. Such as all naturally occurring sodium exists as a compound, ex sodium chloride
Characteristics of Metal
All metals have: a shiny appearance (luster); are good conductors of heat and electricity; exist in a solid state; have high density; and are malleable
What is an ion?
An ion is an atom or group of bonded atoms that has a positive or negative charge.
How many blocks is the periodic table divided into?
The periodic table is divided into four BLOCKS (s, p, d, f) based on which SUB LEVEL is in the process of being filled.
What is the reason why elements within a group share similar chemical properties?
Because the number of valence electrons and the outer electron configuration is constant within a group.
What is the periodic trend for electronegativity?
Electronegativities generally increase from left to right across a period. This is due to an increase in nuclear charge. Alkali metals have the lowest electronegativities, while halogens have the highest. Because most noble gases do not form compounds, they are generally not assigned electronegativity values. Note that there is little variation among the transition metals. Electronegativities generally decrease from top to bottom within a group due to the larger atomic size.
What is electronegativity?
Electronegativity is a measure of the ability of an atom to attract shared electrons when the atom is part of a compound. Electronegativity differs from electron affinity because electron affinity is a measure of the actual energy released when an atom gains an electron. In contrast, electronegativity is a relative scale, so it is not measured in units of energy.
Describe Valence electrons.
Electrons in the outermost occupied principal energy level. The maximum number of valence electrons for an atom in its ground state is eight.
Alkali metals, alkaline earth metals, halogens, and noble gases are the common names of groups ___, ____, ____, and ____
Group 1 (Alkali metals), Group 2 (alkaline earth metals) , Group 17 (halogens) , and Group 18 (noble gases)
Noble gas group
Group 18 at the far right of the periodic table. The elements in this group, called the noble gases, are very unreactive because their outermost s and p sublevels are completely filled.
What is ionization energy?
Ionization energy is the energy required to REMOVE an electron from an atom. The higher the ionization energy, the more difficult it is to remove an electron. Ionization energy is in indicator of reactivity.
What is the trend of Ionization energy across the periodic table?
Ionization energy of atoms generally increases from left to right across each row of the periodic table. This is because of the increase in nuclear charge. A nucleus containing more protons has a larger total positive charge, which results in a greater attractive force being applied to each electron. If the valence electrons are held more tightly to the nucleus by this stronger force, they are more difficult to remove, and more ionization energy is required.
How are Ions formed?
Ions are formed when atoms lose or gain electrons in order to fulfill the octet rule and have full outer valence electron shells.
An element's placement in the periodic table is determined by___________
Its electron configuration.
What is the trend for metallic reactivity?
Metallic reactivity is greatest for elements in the lower left area of the periodic table, while nonmetallic reactivity is greatest for elements in the upper right area.
What is second ionization energy and third and so on?
Multiple electrons can be removed from an atom. If an atom loses two electrons, it acquires a 2+ charge. If an atom loses three electrons, it acquires a 3+ charge, and so on. The second ionization energy of an element is always higher than the first, the third is always higher than the second, and so on. This is because after one ionization, a positively charged ion is formed and there is a greater overall attractive force on the remaining electrons because the protons now outnumber the electrons.
What is the trend for electron affinity?
Period and group trends for electron affinities are not nearly as regular as those for ionization energy. In general, electron affinities increase (become more negative) from left to right across a period and decrease (become less negative) from top to bottom down a group. However, there are many exceptions.
What are actinides?
The actinides are the 14 elements from thorium to lawrencium (atomic number 103). The actinides are all radioactive elements, and only the first four have been found to occur naturally on Earth. All of the others have only been artificially made in the laboratory.
What happens to the ionic radius when you add an electron (anion)?
The addition of electrons always results in an anion that is larger than the parent electron. More electrons means greater electron-electron repulsion.
What is the atomic radius?
The atomic radius is defined as one-half the distance between the nuclei of identical atoms that are bonded together.
What are alkaline earth metals?
The elements in Group 2 of the s block. These elements have two valence electrons, both of which reside in the outermost s sublevel. They tend to be harder, stronger, and denser than the alkali metals, and they also form numerous compounds with nonmetals.
What is the halogen group?
The elements of Group 17 (fluorine, chlorine, bromine, iodine, and astatine) are halogens. The halogens all have the general electron configuration ns2np5, giving them seven valence electrons which makes them very reactive. They undergo especially vigorous reactions with the reactive alkali metals
What is electron affinity?
The energy change that occurs when a neutral atom GAINS an electron is called its electron affinity. That energy is expressed as a negative number. (the opposite of ionization but the same trend as ionization)
Why is the first ionization energy higher for noble gases in relationship to other elements in the period (horizontal)?
The first ionization energies for the noble gases (He, Ne, Ar) are higher than those any other first ionization energy because the noble gases have full outer s and p sublevels, which gives them extra stability and makes them mostly unreactive.
What are lanthanides?
The lanthanides are the 14 elements from cerium (atomic number 58) to lutetium (atomic number 71). They are all metals and are similar in reactivity to the Group 2 alkaline earth metals.
What are the p-block elements.
The p-block consists of the elements in groups 13-18. The properties of the p-block vary widely. The line separating metals from nonmetals runs through the p-block. The number of valence electrons in elements of the p-block is equal to the group number minus 10. Example Group 16, so it has 16 - 10 = 6 valence electrons.
How is the periodic table arranged?
The periodic table is arranged in order of their ATOMIC NUMBER. It is ordered by PERIOD and GROUPS. A PERIOD is a HORIZONTAL row of the periodic table. There are 7 periods in the periodic table, with each one beginning at the far left. A new period begins when a new PRINCIPAL ENERGY (n) level starts filling with electrons. A GROUP is a VERTICAL column of the periodic table and the elements in the same group have similar properties. There are a total of 18 GROUPS.
What are the s-block elements
The s-block consists of the elements in Group 1 and Group 2, which are primarily composed of highly reactive metals.
What are the representative (main-group) elements
The s-block elements and the p-block elements are together called the representative or main-group elements.
What is Coulomb's law?
The strength of a bond between ions of opposite charge can be calculated using Coulomb's Law. Coulomb's law, or Coulomb's inverse-square law, is a law of physics describing the electrostatic interaction between electrically charged particles. Coulomb's Law shows that the force of attraction between two oppositely charged particles is directly proportional to the magnitude of the charges and inversely proportional to the distance between those charges.
What are the inner transition elements?
They are the groups lanthanides and actinides in the f-block.
What are transition elements?
Transition elements are the elements that are found in Groups 3-12 on the periodic table. On the d block
What is the trend in the periodic table for non metallic character
Trend across a period, trends down a group
Characteristics of a non metal
Typical nonmetals characteristics are: dull, coloured or colourless appearance; are brittle when solid; are poor conductors of heat and electricity; are not malliable; can exist in the solid liquid and gas state
What is an anion?
When an atom gains one or more electrons, they become negatively charged and are named ANIONS (-).
What is a cation?
When an atom loses one or more electrons, they become positively charged and are named CATIONS (+).
