Cde Science

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

An atom of a certain element has 36 protons, 36 electrons, and a mass number of 84. At room temperature this element is a very stable gas. How many neutrons are in this atom?

• 36

• 84

• 48

• 72

Tags

NGSS.MS-PS1-1

Any atom that has 19 protons is a potassium (K) atom. Which statement best describes what would happen if a proton was added to potassium atom?

• The atom will lose electrons

• The atom would have a negative charge.

• The atom would no longer be potassium

• The atom would have a smaller atomic number.

Tags

NGSS.MS-PS1-1

Carbon is an element. What is the smallest particle of carbon that has the same chemical  properties of carbon?

• an atom of carbon

• a proton from a carbon atom

• an electron from a carbon atom

• a molecule that contains carbon

Tags

NGSS.MS-PS1-1

What do elements in the same group on the periodic table have in common?

• They have similar chemical symbols

• They have the same atomic number.

• They have similar chemical properties

• They have the same average atomic mass

Which of the following statements best describes pure substances?

• Pure substances consist of substances that have been combined together through physical processes

• Pure substances consist of substances that have been separated through physical processes

• Pure substances are substances that are always made of one type of atoms

• Pure substances consist of substances that have definite physical and chemical properties

Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs), and Francium (Fr) are in the same column in the periodic table. Why are these elements in the same column in the periodic table?

• They are the same size

• They react with each other

• They have similar properties

• They have the same number of protons

Carbon (C) and hydrogen (H) can be chemically combined to form a new substance called methane (CH₄). Which statement below best describes how the new substance compares to carbon (C) and hydrogen (H)?

• The new substance methane (CH4) has the same properties as carbon (C)

• The new substance methane (CH4) has the same properties as hydrogen (H)

• The new substance methane (CH4) has different properties than only hydrogen (H)

• The new substance methane (CH4) has different properties than both carbon (C) and hydrogen (H)

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-2

Which statement is true about the subatomic particles that make up atoms?

• Subatomic particles can be classified as acids, bases, and salts

• The same types of subatomic particles make up all of the elements

• All subatomic particles have either a negative or positive charge

• Subatomic particles retain the properties of elements

Tags

NGSS.MS-PS1-1

John knows that the atomic number of the element Chlorine, Cl, is 17. He also knows that one  particular isotope of chlorine has a mass of 35. How many neutrons can be found in the nucleus of this isotope of chlorine?

• 17

• 18

• 35

• 70