<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>0187-893X</journal-id>
<journal-title><![CDATA[Educación química]]></journal-title>
<abbrev-journal-title><![CDATA[Educ. quím]]></abbrev-journal-title>
<issn>0187-893X</issn>
<publisher>
<publisher-name><![CDATA[Universidad Nacional Autónoma de México, Facultad de Química]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S0187-893X2019000400108</article-id>
<article-id pub-id-type="doi">10.22201/fq.18708404e.2019.4.69562</article-id>
<title-group>
<article-title xml:lang="es"><![CDATA[La afinidad Electrónica, la peor de todas]]></article-title>
<article-title xml:lang="en"><![CDATA[Electron affinity, the &#8220;worst&#8221; periodic property]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Escalante-Tovar]]></surname>
<given-names><![CDATA[Sigfrido]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,Universidad Nacional Autónoma de México Facultad de Química Departamento de Química Inorgánica y Nuclear]]></institution>
<addr-line><![CDATA[ ]]></addr-line>
<country>Mexico</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>00</month>
<year>2019</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>00</month>
<year>2019</year>
</pub-date>
<volume>30</volume>
<numero>4</numero>
<fpage>108</fpage>
<lpage>114</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S0187-893X2019000400108&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S0187-893X2019000400108&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S0187-893X2019000400108&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="es"><p><![CDATA[Resumen Las propiedades periódicas abarcan un conjunto de manifestaciones de la materia que son objeto de análisis en los cursos básicos de las licenciaturas de química. Sus variaciones a lo largo de la tabla periódica son el vehículo para introducir a los alumnos en la relación de los modelos atómicos con propiedades observables y cuantificables macroscópicamente. La afinidad electrónica en particular presenta dificultades para su enseñanza por razones históricas. En este trabajo se retoma un enfoque didáctico que pretende facilitar a los estudiantes la comprensión de esta propiedad y sus variaciones a lo largo de la tabla periódica.]]></p></abstract>
<abstract abstract-type="short" xml:lang="en"><p><![CDATA[Abstract Periodic properties involve a collection of measurable facts of matter that are presented in basic courses of college chemistry. Their variations along the periodic table are studied to introduce the students to the application of atomic models concepts to explain the values of macroscopic observable values. Specifically, electron affinity for historical reasons has some difficulties in the teaching-learning process. This work pretends to reintroduce a didactical scope in the aim to make easier the understanding of this property and their periodic trends as well.]]></p></abstract>
<kwd-group>
<kwd lng="es"><![CDATA[Afinidad electrónica]]></kwd>
<kwd lng="es"><![CDATA[Energía de ionización cero]]></kwd>
<kwd lng="es"><![CDATA[tabla periódica]]></kwd>
<kwd lng="en"><![CDATA[Electron affinity]]></kwd>
<kwd lng="en"><![CDATA[Zeroth ionization energy]]></kwd>
<kwd lng="en"><![CDATA[Periodic table]]></kwd>
</kwd-group>
</article-meta>
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