Chemistry Star Review

The atoms of a certain element each contain 11 protons and 1 valence electron. Which statement correctly identifies this element and describes its chemical reactivity?

• The element is sodium, and it is highly reactive

• The element is fluorine, and is not very reactive

• The element is sodium, and it is not very reactive

• The element is fluorine, and it is highly reactive

Strontium phosphate, Sr₃(PO₄)₂ is a crystalline substance used in medicine and industry. How many phosphorus atoms are represented in the formula for Sr₃(PO₄)₂?

• 2

• 3

• 4

• 8

Tags

NGSS.MS-PS1-1

Students in a science class prepared flashcards so that they could quiz one another about the arrangement of the periodic table. One of the flashcards contained information about two elements, Element L and Element M. The students had to use the information on the flashcard to determine possible positions of the two elements on a blank periodic table. Which periodic table has the elements placed in locations that match the information on the flashcard?

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How many protons, neutrons, and electrons are present in an atom of hafnium, Hf, with a mass number of 178?

• 72 protons, 178 neutrons, 106 electrons

• 72 protons, 106 neutrons, 72 electrons

• 178 protons, 250 neutrons, 72 electrons

• 106 protons, 72 neutrons, 106 electrons

Tags

NGSS.MS-PS1-1

The table shows the chemical formulas for four substances. Which substances have the same number of carbon atoms?

• Substances 1 and 2

• Substances 2, 3, and 4

• Substances 2 and 3 only

• Substances 1 and 3

Tags

NGSS.MS-PS1-1

Tin, Sn, is a soft white metal. It has a low melting point compared with other metals. Tin is widely used as a coating for cans of food. Which statement accurately describes atoms of tin?

• Tin atoms have 50 protons.

• Tin atoms have five valence electrons.

• Tin atoms have 119 neutrons.

• Tin atoms have 68 electrons.

Tags

NGSS.MS-PS1-1

A balance and a graduated cylinder are used to determine the density of a mineral sample. The sample has a mass of 14.7g and a volume of 2.2cm³ .What is the density of the

mineral sample?

• 0.15 g/cm³

• 32 g/cm³

• 13 g/cm³

• 6.7 g/cm³

A researcher wants to experiment with an element that reacts like phosphorus (P) but has a greater atomic mass. Which element should the researcher select for the experiment?

• Nitrogen (N)

• Sulfur (S)

• Arsenic (As)

• Silicon (Si)

A model of an atom is shown. An atom of which element is represented by this model?

• Boron (B)

• Carbon (C)

• Neon (Ne)

• Sodium (Na)

Tags

NGSS.MS-PS1-1

Which of the following best describes an electron?

• It has no charge and about the same mass as a proton.

• It has a negative charge and much less mass than a proton.

• It has a positive charge and much more mass than a neutron.

• It has a negative charge and about the same mass as a neutron.

Tags

NGSS.MS-PS2-3