question

What is probably the most useful tool for chemists?

answer

the periodic table

question

______play most important role in determining the physical and chemical properties of an element.

answer

electrons

question

Arrangment of elements in the periodic table depends on the ______.

answer

properties of elements

question

What are the four categories for classifying elements based on electron configuration?

answer

noble gases, representative elements,transisiton metals, inner transisiton metals

question

What is the group number equal to?

answer

the number of electrons in the outermost energy level

question

______are metallic elements with outermost s sublevel and nearby d sublevel contain electrons.

answer

transition metals

question

Transisiton metals make up ______.

answer

group B elements

question

Transistion metals are characterized by the addition of electrons in _____..

answer

d orbitals

question

______are metallic elements with outermost s sublevel and nearby f sublevel generally contain electrons.

answer

innertransition metals

question

What are inner transistion metals characterized by?

answer

the filling of the f orbital

question

The s block corresponds to the the groups ____and____elements.

answer

one a and two a

question

What each period number represent?

answer

principle energy levels

question

Atoms do not have_____and the _____of an atom cannot be directly measured.

answer

definite size; radius

question

______is used to estimate atomic radii of crystalline structures

answer

x-ray diffraction

question

For diatomic molecules, what is the radius?

answer

1/2 the distance between the nuclei of the two atoms

question

Atomic radius indicates_____.

answer

relative size

question

Atomic size generally _____as you move down a group in the periodic table.

answer

increases

question

What are the two competing factors that affect atomic size?

answer

electron shielding and effective nuclear charge

question

Why does electron sheilding tend to increase the atomic radius?

answer

because electrons added to higher energy levels don't feel full force of nuclear charge

question

Outer electrons are _____from the nuclear charge.

answer

shielded

question

Why does effective nuclear charge tend to shrink atomic size?

answer

because of the attractive force between the nucleus and the electrons

question

What happens to the shielding as electrons are added to higher principle energy levels?

answer

the shielding of electrons offsets the increased charge of the nucleus

question

Why are cations smaller than the neutral atoms?

answer

because of the attraction of the nucleus on fewer electrons

question

Why are anions larger than the neutral atom?

answer

because the inner electrons shield the extra electron

question

Atomic size generally _____as you move from left to right across the period.

answer

decreases

question

The shielding effect is ____across a period.

answer

constant

question

The increased nuclear charge pulls the outermost electrons inward. What does this do?

answer

decreases the atomic size

question

The energy required to overcome the nuclear charge and remove an electron from a gaseous atom is called the______.

answer

ionization energy

question

What is first ionization energy?

answer

the energy required to remove the outermost electron is

question

What is second ionization energy?

answer

;the energy required to remove the second outermost electron

question

What is the main difference between the first and second inonization energies?

answer

it easy to remove on electron, but difficult to remove others

question

What two factors affect ionization ergy?

answer

nuclear charge and distance from the nucleus

question

Why does first ionization energy generally decrease down a group?

answer

because as you move down the group, the electrons are farther from the nucleus and more easily removed

question

Why does first ionization energy generally increase from left to right across a period?

answer

;because nuclear charge increases and shielding is constant which causes;a greater attraction of the nucleus for electrons, making it harder to remove an electron

question

Whether an atom gains or loses an electron affects its______.

answer

ionic size

question

Why are anions generally larger than the neutal atoms?

answer

the nuclear attraction is less for the increased number of electrons

question

____generally increases down the group.

answer

ionic radius

question

From left to right across a period ____ gradually decrease in size.

answer

cations

question

The_____of an element is the tendency of the atoms of the element to attract electrons;when bonded to another atom.

answer

electronegativity

question

Where does the electronegativity of representative elements decrease? When does it increase?

answer

decreses down the group; increases left to right across the period.

question

When does atomic radius increase? When does it decrease?

answer

down a group; down a period

question

What is the difference between a group and a period?

answer

a group is the column and a period is the row

question

Which are larger: cations or the neutral atoms from which they form?

answer

neutral atoms from which they form

question

What;does electronegativity measure?

answer

the ability of a bonded atom to attract electrons to itself

question

When does electronegativity decrease? When does it increase?

answer

down the group; across the period

question

Would halogens have low or high electronegativities?

answer

high

question

How many orbitals are the 4p energy level?

answer

three

question

Do electrons pair up in each orbital before filling additional ones?

answer

no

question

To occupy the same orbital, what must electrons have?

answer

opposite signs

question

Bohr discovered that electrons have fixed amounts of energy, they do not_____energy and cannot fall into the ____.

answer

nucleus

question

What is a quantam of energy?

answer

the amount of energy needed to raise an electron to the next higher level

question

ARe energy levels evenly spaced?

answer

no

question

When is the electron cloud more dense?

answer

when the probability of finding an electron is high

question

Regions in which electrons are likely to be found are called______.

answer

atomic orbitals

question

Within each principle energy level, electrons occupy _____.

answer

energy sublevels

question

Atomic orbitals are designated with what letters?

answer

spdf

question

What shape is the s orbital? What shape is the p orbital? What shape is the d orbital? What shape is the f orbital?

answer

spherical; dumbell shaped; clover leaf; very complex

question

What does the principle quantam number tell about electrons?

answer

the maximum number of electrons in that principle energy level

question

What letter represents the principle quantam number?

answer

n

question

How many electrons are in the s sublevel? p? d? f?

answer

2; 6; 10; 14

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