Mendeleev noticed blank spaces in his periodic table. What did he believe these were?

• an anomaly

• isotopes

• undiscovered elements

• compounds

In the modern periodic table, elements are arranged according to _______.

• decreasing atomic mass

• Mendeleev's original model

• Moseley's model - by increasing atomic number

• when they were discovered

Group 17 elements, the halogens, are the most reactive of the nonmetals because they _____.

• require only one electron to fill their outer energy level

• have the highest ionization energies

• have the largest atomic radii

• are the farthest right in the periodic table

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NGSS.HS-PS1-1

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What group and period is the following element found in? 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s¹

• Group 3 / Period 4

• Group 1 / Period 5

• Group 10 / Period 6

• Group 5 / Period 1

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NGSS.HS-PS1-1

Which of the following has the smallest atomic radii: Al, Mg, Si or Na?

• Aluminium (Al)

• Magnesium (Mg)

• Silicon (Si)

• Sodium (Na)

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Elements in the same ______ share similar properties.

• period

• group

• row

• sublevel

Which of the following hypothetical elements will most likely form a 1+ ion?

• Q: 3s²3p⁵

• R: 3s¹

• T: 4d¹05s²5p⁵

• X: 4d¹05s²5p¹

Tags

NGSS.HS-PS1-1

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Of the following elements which has the highest electronegativity? Ga, Br, or Ca?

• gallium (Ga)

• bromine (Br)

• calcium (Ca)

• selenium (Se)

As you go left to right in Period 3, from Mg to Cl, the energy needed to remove an electron _?

• generally increase

• generally decrease

• does not change

• varies unpredictably

Tags

NGSS.HS-PS1-1

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Rank the elements Sr, Te, Kr, Ru, and Cs in order of increasing ionization energy.

• Sr < Te < Ru < Cs < Kr

• Te < Ru < Sr < Cs < Kr

• Cs < Sr < Ru < Te < Kr

• Kr < Cs < Sr < Ru < Te

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2