Science - Atoms, compounds, bonds

What made all of the naturally occurring elements?

• Chemical reactions in the atmosphere.

• Nuclear fusion and supernova explosions. The Big Bang

• Volcanic activity on Earth.

• Radioactive decay of elements.

Answer explanation

Naturally occurring elements were primarily formed through nuclear fusion in stars and during supernova explosions. The Big Bang also contributed to the formation of the lightest elements, making this the correct answer.

Tags

NGSS.HS-ESS1-1

NGSS.HS-ESS1-3

When a compound is created what is formed?

• No change occurs in the original substances.

• A mixture of elements is formed.

• A new substance is formed.

• Only energy is released.

Answer explanation

When a compound is created, the original substances undergo a chemical change, resulting in the formation of a new substance with different properties. Thus, the correct answer is that a new substance is formed.

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-2

NGSS.MS-PS1-5

What must happen for a compound to be formed?

• Atoms must be destroyed to form a compound.

• Only one type of atom is needed to create a compound.

• A chemical reaction

• Compounds can form without any atomic interaction.

Answer explanation

A compound is formed through a chemical reaction, where atoms interact and bond together. The other options are incorrect as they misrepresent the nature of atomic interactions necessary for compound formation.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

How many elements are there on the periodic table?

• 118

• 100

• 115

• 120

Answer explanation

The periodic table currently has 118 confirmed elements, ranging from hydrogen (atomic number 1) to oganesson (atomic number 118). Therefore, the correct answer is 118.

How many elements are there on the periodic table?

Answer explanation

The periodic table currently has 118 confirmed elements. Therefore, the correct answer is 118, not 0.

What do you call the letters on the periodic table?

• Chemical formulas

• Element names

• Atomic numbers

• Chemical symbols

Answer explanation

The letters on the periodic table are called chemical symbols. Each element is represented by a unique one or two-letter symbol, which is used to identify it in chemical formulas and reactions.

When elements combine to form a compound?

• When elements are mixed physically.

• When elements undergo a chemical reaction.

• When elements are heated together.

• When elements are stored in a container.

Answer explanation

Elements combine to form a compound when they undergo a chemical reaction, resulting in new substances with different properties. Physical mixing or heating does not guarantee a chemical change.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

What does a chemical formula show?

• A chemical formula describes the physical state of a substance.

• A chemical formula indicates the temperature of a substance.

• A chemical formula shows the color of a substance.

• A chemical formula shows the types and quantities of atoms in a substance.

Answer explanation

A chemical formula provides essential information about a substance by showing the types and quantities of atoms it contains, which is crucial for understanding its composition and properties.

Tags

NGSS.MS-PS1-1

H is the symbol for what element?

• Hydrogen

• Oxygen

• Helium

• Carbon

Answer explanation

H is the chemical symbol for Hydrogen, the lightest and most abundant element in the universe. It is essential for the formation of stars and is a key component of water.

What is the symbol for Hydrogen?

Answer explanation

The symbol for Hydrogen is 'H'. This is the standard one-letter abbreviation used in the periodic table to represent the element Hydrogen.