physical science chapter 5

Suppose you are looking at elements in the periodic table in this order: element 23, element 24, element 25, element 26, and so on. Are you looking across a period or down a group? Explain your answer.

I am looking across the period because the atomic number is increasing by one.

Inferring Find the block labeled ? in Figure 5-2. Predict the properties of this element. What is its atomic number? How many valence electrons does it have? Which of the elements shown in Figure 5-2 will it most resemble?

-It is going to be highly reactive, it's an alkali and earth metal, atomic number is 12, has 2 valence electrons, and it most resembles beryllium

Using Tables and Graphs Which elements in Figure 5-2 have the same number of valence electrons? How do you know?

-The elements have the same number of electrons fluorine and iodine because they are in the same group

Comparing and Contrasting Based on what you know about elements and the periodic table, compare and contrast the elements beryllium (Be) and iodine (I).

-The elements in the periodic table are both metals. Iodine is more reactive because it 7 valence electrons but beryllium only has 2.

Classifying Which element in Figure 5-2 is a transition metal? Which is a noble gas?

-V is transition metal and helium is a noble gas

Why is argon gas used instead of air in light bulbs that contain a filament that is heated to glowing?

Argon gas is used in a light bulb instead of air because it is unreactive.

Sodium chloride is a compound of sodium and chlorine. Which of these Elements is the alkali metal, and which is the halogen?

Sodium in the alkali metal and chlorine is the halogen

Using Tables and Graphs Which of the elements shown in Figure -5-2 are in the same period?

The elements that are in the same period is beryllium, carbon, nitrogen, and fluorine

1. Why were the elements gallium (Ga), scandium (Sc), and germanium (Ge) important to Mendeleev?

These elements are important to Mendeleev because it showed that his predictions were pretty accurate and organized.

On the periodic table, there are two numbers in the block for the element krypton (Kr): 36 and 83.80. What are each of these numbers, and what do they represent?

These number represent atomic number, 36, and atomic mass. The atomic number is 36 and the atomic mass

What determines an element's chemical properties?

by the number of valence electrons.