Elements

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A substance that cannot be broken down chemically into simpler substances is a(n) ___________.

• atom

• electron

• element

• nucleus

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Today we know that a(n) ___________ is the smallest unit of an element that has that element's properties.

• atom

• electron

• element

• nucleus

Tags

NGSS.MS-PS1-1

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Negatively charged particles called ___________move around the nucleus.

• atom

• electrons

• elements

• neutron

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Because an atom has the same number of ___________ and electrons, the atom has no overall charge.

• protons

• electrons

• elements

• neutron

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On Earth, elements such as ___________ and any of these: oxygen, silicon, aluminum, nitrogen, iron and calcium are among the most common.

• oxygen

• hydrogen

• elements

• helium

Tags

NGSS.MS-PS1-1

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Dmitri Mendeleev created the _______ table of elements.

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In space, the most common elements are __________ and __________.

Tags

NGSS.HS-ESS1-3

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The center of an atom is its ________.

The atomic number tells you what?

• number of electrons
• number of protons
• number of neutrons
• both electrons and protons in an atom.

The atoms along the staircase are called 

• metals
• nonmetals
• metalloids
• noble gases