Unit 4

Front

Back

Periods

Front

The atomic number tells you what?

Back

number of protons

Answer explanation

The atomic number of an element is defined as the number of protons in its nucleus. Since protons determine the element's identity, the correct answer is 'number of protons'.

Front

In the modern periodic table, elements are arranged by:

Back

atomic number

Answer explanation

In the modern periodic table, elements are arranged by atomic number, which is the number of protons in an atom's nucleus. This arrangement reflects the periodic law, where properties of elements recur periodically with increasing atomic number.

Front

The periodic table is organized into columns called groups and rows called periods.

Back

groups and periods

Answer explanation

The periodic table is organized into columns known as groups and rows known as periods. Therefore, the correct answer is 'groups and periods'.

Front

Which group of the periodic table is composed of inert (non-reactive) gases?

Back

Noble gases

Answer explanation

The noble gases, found in Group 18 of the periodic table, are known for their lack of reactivity due to having a full valence shell of electrons. This makes them inert compared to alkali metals, alkaline earth metals, and halogens.

Front

Elements that are shiny and conduct electricity and heat are called

Back

metals

Answer explanation

Elements that are shiny and conduct electricity and heat are classified as metals. Nonmetals are typically dull and poor conductors, while metalloids have mixed properties. Therefore, the correct answer is metals.

Front

The atoms along the stair-step or zigzag line are called

Back

metalloids

Answer explanation

The atoms along the stair step line on the periodic table are known as metalloids. They exhibit properties of both metals and nonmetals, making them unique in their classification.

Front

The yellow atoms are called

Back

non-metals

Answer explanation

The yellow atoms are classified as nonmetals. Nonmetals are elements that typically lack the properties of metals, such as conductivity and malleability, and are often found in gaseous or brittle solid forms.

Front

Which element is not in the alkali metal family? Options: Li, H, Fr, Cs

Back

H

Answer explanation

Hydrogen (H) is not an alkali metal; it is a non-metal. The alkali metals include lithium (Li), cesium (Cs), and francium (Fr), which are all in Group 1 of the periodic table.

Front

Which of the three major groups contains the most elements?

• Metals
• Metalloids
• Nonmetals

Back

Metals

Answer explanation

The group of Metals contains the most elements among the three major groups. Metals are abundant in the periodic table, while Metalloids and Nonmetals have significantly fewer elements.