Name Date Class

Chapter 6 • The Periodic Table SMALL-SCALE EXPERIMENT

A PERIODIC TABLE LOGIC PROBLEM

OBJECTIVES

Analyze properties and relationships of 26 elements.

Identify each element’s place in the periodic table based on these properties and relationships.

INTRODUCTION When elements are arranged in the periodic table in order of increasing atomic number, there is a periodic repetition of their

physical and chemical properties. The way properties change from left to right across a period and from top to bottom within a

group are called periodic trends. Here is a summary of some periodic trends.

Atomic size can be expressed by a measurement called the atomic radius. Atomic radius is one half the distance between the

nuclei of two atoms of the same element when the atoms are joined. The atomic radius generally increases from top to bottom

within a group. The atomic radius generally decreases from left to right across a period.

Ionization energy is the energy required to remove an electron from an atom. This energy is measured when the atom is in the

gaseous state. The first ionization energy is the energy required to remove the first electron from an atom. The second ionization

energy is the energy required to remove an electron from a cation with a 1+ charge. The third ionization energy is the energy

required to remove an electron from a cation with a 2+ charge. The second ionization energy for an element is always larger than

the first ionization energy. The third ionization energy is always larger than the second ionization energy. In general, first

ionization energy decreases from top to bottom within a group and increases from left to right across a period.

Electronegativity is the ability of an atom of an element to attract electrons when the atom is in a compound. In general,

electronegativity values decrease from top to bottom within a group and increase from left to right across a period. Because noble

gases do not tend to form compounds, electronegativity values for noble elements are usually omitted from data tables.

Metals tend to have low first ionization energies and low electronegativity values. Nonmetals tend to have high first ionization

energies and high electronegativity values.

PURPOSE

In this experiment, you will use a series of clues to arrange a set of unknown elements in a periodic table. The elements are the

elements with atomic numbers 1–20 and 31–36. A letter of the alphabet is used to represent each unknown element. The letter

designation is not related to an element’s chemical symbol. Each clue refers to a property of an element or a relationship an element

has to other elements in the periodic table. Along with logic and knowledge of properties, you will use periodic trends to solve the

puzzle. When you are done, each element will be in its unique place on the table. Good luck!

EXPERIMENTAL PROCEDURE

Use the following periodic trend clues to place the elements in their proper places in the short form of the periodic table provided.

A Has one of the highest electronegativities on the table

B Has one electron in a 3p orbital

C Has five electrons in the fourth energy level

D Forms the smallest 2 ion

E Tends to gain one electron

F Electronic configuration is 1s22s

22p

63s

23p

3

G Is the most electronegative element

H An ion of this element with a 2 charge has 18

electrons.

I Its second ionization energy is large compared to its

first ionization energy.

J Its highest occupied energy level is full.

K This nonmetal is likely to form an ion with a 3

charge.

L Has the highest first ionization energy in the table

M Has the smallest atomic radius in the third period

N Is the smallest atom in its group

O The first element with an electron in the second

energy level

P The only nonmetal in a group with highly reactive

metals

Q Has eight fewer protons than its “groupmate” H

R The most likely element of the ones included to lose

an electron

S A metalloid in period 4

T Its ionic radius is larger than its atomic radius.

U The ion with a 2 charge that it forms has 18

electrons.

V Atomic number is 34

W Metalloid that forms an ion with a 3 charge

X Has characteristics of both a metal and a nonmetal

Y Has a lower first ionization energy than S

Z Has a first ionization energy that is higher than T but

lower than M

EXPERIMENTAL DATA Using the clues given in the Experimental Procedure, place the letter of each element in its place on the following short

form of the periodic table.

QUESTIONS FOR ANALYSES

1. Which elemental clues contain sufficient information to place the element, using no other information?

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2. Excluding elements identified in your answer to Question 1, for which clues could you identify a group based solely

on an individual clue?

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3. Which elements were you able to place based on electronegativity?

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4. Which of the following properties increase from top to bottom within a group?

Which increase from left to right across a period?

a. first ionization energy

b. electronegativity

c. atomic radius

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